B R I T I S H H Y D R A U L I C E N G I N E E R I N G A N D R E S E A R C H
B Y J . A L L E N
PROFESSOR OF ENGINEERING, DEPARTMENT OF ENGINEERING, MARISCHAL COLLEGE, UNIVERSITY OF ABERDEEN
O u r knowledge of the m o t i o n o f water along pipes and open channels, and of the i n t e r a c t i o n between the l i q u i d and the solid boundaries, is based o n w o r k done i n m a n y d i f f e r e n t countries. Indeed, i t is sometimes rash to assert that any one person was the discoverer o f a p a r t i c u l a r new fact or theory or experimental technique. T h e a i m o f this essay is not to c l a i m p r i o r i t y i n time or importance b u t rather to outline some o f the past British contributions t o hydraulics, whether u n i q u e or not, and to indicate Avhat is being attempted at the present time.
B r o a d l y speaking, there have been three m a i n categories o f a c t i v i t y : (i) the mathematical and philosophical (as i n the classical w r i t i n g s o f Sir George G a b r i e l STOICES (1819-1903) and Sir Horace L A M B (1849¬
1934) ) covering a wide range of w h a t we describe as hydrodynamics as distinct f r o m h y d r a u l i c s ; (ii) the more experimental attack, guided b y various degree o f m a t h e m a t i c a l insight occasionally o f a h i g h order (as i n the w o r k of Osborne R E Y N O L D S (1842-1912) a n d more recently o f Sir Geoffrey T A Y L O R ) ; ( i i i ) t h e i n v e n t i o n o f h y d r a u l i c appliances or their a p p l i c a t i o n to p a r t i c u l a r purposes, as f o r example the use o f h y d r a u l i c j a c k s b y R o b e r t STEPHENSON (1803-1859) and I s a m b a r d K . B R U N E L (1806—1859) i n raising heavy girders d u r i n g the construc-t i o n of construc-their greaconstruc-t bridges or Sir W i l l i a m A R R O L ' S " h y d r a u l i c spade" for excavating h a r d boulder clay at the pier foundations of the F o r t h R a i l w a y Bridge (1883-1890). Indeed, the 19th century applications o f h y d r a u l i c power i n B r i t a i n , as elsewhere, seem to have b e e n almost limitless: t h e " h y d r a u l i c a c c u m u l a t o r " of L o r d A R M S T R O N G (1810-1900) overcame t h e d i f f i c u l t y t h a t certain mechanical operations involve short
periods of heavy demand for power followed b y idleness and thus increased the a p p l i c a t i o n o f water power to cranes, lifts and other machines; the h y d r a u l i c press came i n t o prominence for such widely d i f f e r e n t purposes as b a l i n g cotton, f l a n g i n g boilei'-plates and f o r g i n g massive ingots of steel. Previous to the general advent of electrical transmission, the d i s t r i b u t i o n of energy to private consumers by delivering water under pressure f r o m a central p u m p i n g station was adopted i n cities such as L o n d o n , Glasgow and Manchester.
I t is d i f f i c u l t indeed f o r us to visualize or to appreciate the i m p a c t o f the i n d u s t r i a l revolution. W e are conscious of the phenomenal rate o f g r o w t h of science i n our o w n time but the 19th century developments i n h y d r a u l i c engineering considered i n its widest sense were also remarkable. I t was a period w h i c h presented an urgent challenge to engineers, i f o n l y because of the r a p i d changes i n p o p u l a t i o n , not j u s t n u m e r i c a l l y b u t also i n the nature o f its d i s t r i b u t i o n . Thus, i t is said that the t o t a l p o p u l a t i o n o f Great B r i t a i n rose f r o m some 10.5 millions at the d a w n o f the 19th cen-t u r y cen-to 23 milHons b y cen-the year 1860 and cen-to 37 millions by cen-the close of the century. A t the same time, the urban p o p u l a t i o n increased f r o m 3 millions i n 1801 to neariy 13 milHons i n 1861 and to f u l l y 28 millions i n 1901. W e can at least imagine the effect o f these phenomena on the demands f o r an adequate supply o f water f o r domestic and i n d u s t r i a l purposes. T o meet these needs, the energies of engineers like Thomas H A W K S L E Y (1807-1893), J o h n Frederic L a T r o b e B A T E M A N (1810-1889), James M A N S E R G H (1834-1905) and Sir Alexander B I N N I E (1839-1917) were largely devoted to water supply projects, and rules f o r estimating the y i e l d o f catchment areas and the storage o f reservoirs were f o r m u l a t e d by H A W I C S L E Y (1868) and BTNNIE (1892). Moreover, the p u r i f i c a t i o n of water assumed an added importance, although i t is realised that some methods of p u r i f y i n g water f o r d r i n k i n g purposes were practised i n China, Egypt and I n d i a thousands o f years ago. Possibly the most significant advance i n m o d e r n times was the large-scale use o f filtration t h r o u g h sand, for w h i c h apparently a patent was taken out i n 1791 by James PEACOCIC (1738-1814). " S l o w sand filters" were b u i l t at Paisley
(Scotland) i n 1804 by J o h n G I B B (1776-1850) and at Greenock (Scot-land) i n 1827 by R o b e r t T H O M (1774-1847), while James SIMPSON (1799¬ 1869) not only designed works o f t h i s sort but also studied their mode of action systematically, so that b y 1852 the filtration o f a l l water for
household use i n L o n d o n was prescribed except i n the case o f deep w e l l water p u m p e d i n t o covered reservoirs. Similar advances were made i n sewerage by the adoption of sewers for h u m a n waste and other noxious matter and by the development of methods of sewage treatment.
A t the same time, the expansion of trade and industry led to m a n y interesting canal and harbour works, and one cannot help a d m i r i n g the extraordinary courage and persistence o f some o f the engineers i n basing their designs and their methods of construction very largely on their o w n experience and i n t u i t i o n , unaided by laboratory testing as we know i t to-day. A m o n g the works which can t r u l y be described as " d a r i n g " were the creation and improvement of port facilities near to centres of industry and commerce, often i n the face of immense n a t u r a l obstacles and m a n -made opposition and comphcated by the increasing draught of ships. T h e docks and channels of the Thames, the Clyde, the Mersey and the R i b b l e a l l provide striking examples of development. I t is amazing to read that a chart prepared by J o h n SMEATON (1724-1792) shows a depth o f less t h a n 4 feet (1.22 metre) at a p o i n t i n the Clyde close to the site o f the launching of the "Queen M a r y " i n 1934, while the annual number of vessels entering the Thames increased f o u r - f o l d between 1800 and 1890, accompanied by a m u c h greater rise o f tonnage, and a new, m a j o r p o r t was created at Manchester by the construction (1887-1894) of the 35 mile-long Manchester Ship Canal having a designed b o t t o m w i d t h and depth of 120 feet (36.5 m) and 26 feet (7.9 m ) respectively. Part of the vast excavation f o r this canal consisted o f approximately ten m i l h o n cubic yards (7.6 m i l l i o n cubic metres) of sandstone rock. I n some instances, notably i n L i v e r p o o l Bay and the estuary of the R i b b l e (port o f Preston), t r a i n i n g walls o f dumped stone were b u i l t w i t h the object of concentrating the currents to m a i n t a i n the navigable channels. Steam-operated dredgers appeared o n the Clyde i n 1824 and i n the R i b b l e i n 1839, while the scale o f dredging advanced to such an extent that b y the end of the 19th century, the fleet of dredgers operating o n the channels leading to the port o f L i v e r p o o l included the suction vessel " L e v i a t h a n " , having a capacity o f 180,000 cubic feet (5,100 cubic metres) and able to fiU herself i n 50 minutes. M a n y ingenious dredging devices were tried about this period. As far back as the late 18th century, some success had been achieved i n deepening the Clyde by means of ploughs d r a w n by horses to loosen sand w h i c h dried at low water and of special ploughs and
harrows worked by hand-capstans situated on the river-bank, the loosened material being carried away on the ebb tide. M u c h later (circa 1889), at T i l b u r y Docks, the m u d deposits i n a t i d a l basin were encouraged to f l o w out w i t h the tide by p u m p i n g water t h r o u g h tubes w h i c h trailed along the bed.
Clearly, this was an exciting age i n the history o f hydraulic engineering. A t Exhibitions held i n B i r m i n g h a m and L o n d o n about the year 1850, James Stuart G w Y N N E (1831-1915) a n d j o h n George A P P O L D (1800-1865)
showed centrifugal pumps. Professor James T H O M S O N (1822-1892) sug-gested the use of a " w h i r l p o o l chamber" to enhance the efficiency of centrifugal pumps; one such p u m p was constructed for drainage works i n Barbados having impeller and w h i r l p o o l chamber diameters o f 16 and 32 feet respectively (4.88 and 9.75 m ) . T H O M S O N also reported the results of his experimental researches on a practical f o r m of j e t - p u m p and con-t r i b u con-t e d a paper of oucon-tscon-tanding incon-terescon-t con-to con-the Bricon-tish Associacon-tion for con-the Advancement of Science i n 1852 describing his ideas on the i n w a r d - f l o w water turbine, i n c l u d i n g the concept of pivoted guide-vanes the openings between w h i c h could be adjusted so as to regulate the supply o f water to the runner. A g a i n , at the British Association meeting o f 1877, Osborne R E Y N O L D S told how he had used a centrifugal p u m p suspended on the shaft o f a multiple steam-turbine f o r measuring its power-output at speeds up to 12,000 revolutions per minute. The same M e e t i n g heard W i l l i a m F R O U D E (1810-1879) on his o w n distinctive f o r m of hydraulic dynamo-meter f o r gauging the power of large engines (a device subsequenuy studied and i m p r o v e d by R E Y N O L D S and used by h i m i n his great deter-m i n a t i o n o f the "deter-mechanical equivalent of h e a t " ) .
T h e Fen country of East A n g l i a is one p a r t o f the British Isles w h i c h resembles the Netherlands and w h i c h has presented somewhat similar engineering problems i n drainage and reclamation. F r o m the 17th cen-t u r y , cen-the "scoopwheel" (racen-ther like a reversed wacen-ter-wheel and driven by windmills) had been used for p u m p i n g , b u t by 1820 a 30-horsepower steam-driven p u m p was brought i n t o service and early i n the 1850's, a centrifugal p u m p was used to d r a i n 1,000 acres of Whittlesey Mere w h i c h soon produced its fields of yellow corn. T r a i n i n g walls for the rivers W e l l a n d and Great Ouse employed the characteristic D u t c h method of construction by fascines. A b r o a d , i n I n d i a and Egypt, remarkable feats of i r r i g a t i o n were achieved, i n c l u d i n g the Ganges Canal and the U p p e r
Bari Doab Canal (opened i n 1859), while the i n t r o d u c t i o n of the c u l t i v a t i o n o f cotton to L o w e r Egypt i n 1826 w i t h its need o f " p e r e n n i a l i r r i g a -t i o n " led -to -the cons-truc-tion over -the nex-t hundred years o f m a j o r works such as the Delta Barrages (1861), at first only p a r t l y usable, and the Asyut and Aswan dams, incorporating steel gates of the "Stoney" type. I have given this brief account of hydraulic engineering i n the o l d days, and especially d u r i n g the 19th century, i n order to provide a background and, i n some ways, an explanation of later events. O u r distinguished colleague Professor THIJSSE w i l l agree w i t h me, I think, t h a t certain significant facts emerge f r o m this history. One of these is the magnitude of some o f the works executed or attempted w i t h o u t the guidance o f highly developed theories or the assistance of laboratory experiments. Yet there is also evidence o f a changing attitude; the feeling that perhaps f u r t h e r developments and improvements m i g h t be more confidently undertaken i f experience and i n t u i t i o n could be supplemented b y more f u n d a m e n t a l knowledge and controlled experiment. U n d o u b t e d l y "the w i n d of change" sprang p a r t l y f r o m the qualities of academic men who had the happy f a c i f i t y of c o m b i n i n g their philosophical attitude w i t h considerable practical gifts as engineers. N u m b e r e d among these ver-satile men i n B r i t a i n were university professors such as H . G. F . J E N K I N (1833-1885) ( E d i n b u r g h University), W . J . M . RANICINE (1820-1872) (Glasgow), Osborne R E Y N O L D S (18421912) (Manchester), James T H O M -SON (1822-1892) (Belfast and Glasgow), and W . G. U N W I N (1838-1933) ( L o n d o n ) , while others like W i U i a m F R O U D E (1810-1879) had the same virtuosity. I have already referred to a few of the " p r a c t i c a l " interests of some of these, and i t is useful to consider one or two i n greater detail. THOMSON'S interests were not confined to hydraulic machinery; he also propounded his w e l l - k n o w n theory o f transverse currents at bends i n open channels to account for the f o r m a t i o n of sandbanks at the inner sides o f rivers. F R O U D E , i n a d d i t i o n to his mechanically ingenious h y d r a u l i c brake, is honoured i n the eponymous nomenclature o f fluid mechanics by the attachment o f his name to the dimensionless q u a n t i t y vj ^/gl, and he introduced the technique o f predicting the resistance o f ships w i t h the aid of scale models.
T h e outstanding example, however, is that o f Osborne R E Y N O L D S , whose w o r k commanded a d m i r a t i o n among engineers, mathematicians a n d physicists alike and must, therefore, have encouraged the recognition o f
engineering as a "respectable science". H o w could i t be otherwise when practising engineers realised that this erudite professor had designed w h a t was p r o b a b l y the most efficient triple-expansion steam engine o f its day, or the physicist read his papers on the two manners of m o t i o n o f water and the circumstances w h i c h determine whether the m o t i o n shall be "direct or sinuous" and his speculations on the "sub-mechanics of the universe", or the mathematician browsed over his h y d r o d y n a m i c theory of lubrication? A t r u l y remarkable feature of R E Y N O L D S was the w a y i n w h i c h he brought his m i n d to bear on practical problems o f the t i m e : i f he heard o f cases o f failure of locomotive coupling-rods, he applied his attention to the subject of inertia stresses and the f u n d a m e n t a l limits to speed; w h e n he was saddened by the news of a lifeboat disaster, he enun-ciated the laws o f similarity w h i c h should be obeyed i n carrying our scale-model tests o f the seagoing qualities o f boats; and one imagines that learning o f the controversial discussions on the placing o f training-walls i n estuaries like the R i b b l e was p a r t l y responsible f o r his pioneering experiments w i t h t i d a l models. I n B r i t a i n , the f u l l benefit o f this method of investigation was not to be accepted for many years after R E Y N O L D S died. W h i l e laboratories i n other countries were studying river problems i n scale-models, an attitude o f apathy or scepticism remained among British engineers. Perhaps this was another f o r m of legacy f r o m the earher days; so m u c h has been done on the basis of j u d g m e n t and " c o m m o n sense", and again there was the persistent reluctance to believe i n river models w h i c h unavoidably used bed-materials whose i n d i v i d u a l grains were described as being equivalent to huge boulders.
The revival o f interest among British engineers i n the use o f river models dates f r o m 1 9 2 6 , when Professor A . H . GIBSON ( 1 8 7 8 - 1 9 5 9 ) began his scale-model investigation of the possible effects of a proposed t i d a l power barrage on the tides, currents and navigable channels o f the Severn estuary. GIBSON had been a student o f R E Y N O L D S and exhibited some of his versatility i n research by his work i n fields as different as "structures", aero-engines, the viscosity of air, the resistance to flow along divergent pipes and corrugated tubes, vortex-motion and the flow-characteristics of siphon-spillways, the volute chambers of centrifugal pumps and the draught-tubes of turbines. GIBSON'S experiments on his t i d a l models are remembered p a r t l y because of his tests on bed-materials o f various sizes and densities and o f his i n t r o d u c i n g suspensions of fine silt.
Later investigations i n GIBSON'S laboratories at Manehester related to proposed works i n L i v e r p o o l Bay, the H u m b e r , the Dee ( w h i c h flows t h r o u g h Chester), the Barrett (which has its o u t f a l l i n the Bristol C h a n -nel), a non-tidal p o r t i o n of the river Mersey (this included a study o f the relative importance of " f o r m d r a g " and "skin f r i c t i o n " ) , the experi-mental verification of theories of tide-propagation due to Sir Horace L A M B and Sir GeoflFrey T A Y L O R , and d u r i n g the Second W o r l d W a r experiments to assist i n assessing the stability o f causeways designed to close the eastern approaches to the naval anchorage at Scapa F l o w . GIBSON'S influence can also be detected i n the tidal-model investigations made by Sir Alexander G I B B and Partners (consulting engineers) f o r their report on the problem of the channel over the outer bar leading to the p o r t o f Rangoon and by the Great Ouse River Board for the study o f a scheme of flood protection. I know how interested Professor THIJSSE was i n this model of the Wash and the Great Ouse.
Towards the end of the W a r , thoughts turned towards the desirability o f establishing a national hydraulics research station w h i c h m i g h t u l t i m a t e l y enjoy facilities similar to those i n other countries, i n c l u d i n g the famous D e l f t laboratory among whose notable works had been the experiments on breakwaters for the port of L e i t h i n Scotland.
T w o former Presidents o f the I n s t i t u t i o n of C i v i l Engineers i n L o n d o n
- Sir W i l h a m H A L C R O W (1883-1958) and M r . F. E. W E N T W O R T H - S H E I L D S
(1869 1959) - were p r o m i n e n t i n the move for a British national labo-ratory for w o r k i n "loose-boundary hydraulics", and i n 1946 the Depart-ment of Scientific and I n d u s t r i a l Research decided to f o r m the necessary organization under the direction of Sir Claude I N G L I S (1883- ) . T h e decision has led to the D . S . I . R . Hydrauhcs Research Station at W a l l i n g -f o r d , Berkshire, a site chosen by Sir Claude INGLIS, who retired i n 1958 and was succeeded as Director by M r . Fergus H . A L L E N .
I N G L I S may be said to have had two distinguished careers; one i n I n d i a where he was responsible for many i m p o r t a n t investigations o f rivers and canals w i t h the aid of models and the second i n establishing the British Hydraulics Research Station. M e n t i o n o f his " f i r s t career" recalls m y earlier reference to engineering activities i n I n d i a , because these also have had significant results i n the f o r m of the " r é g i m e theory". T h e first h a l f of the 19th century saw the b u i l d i n g of what have been described as "possibly the first permanent canal works o f any magnitude
con-structed d u r i n g tlae British a d m i n i s t r a t i o n " . A n i m p o r t a n t corollary of this was the observation that the excessive gradient of a canal o n the Eastern J u m n a system resulted i n heavy scour and damage to masonry works, whereas previous experience had commonly been o f canals giving trouble by silting. F r o m that time onwards, engineers i n I n d i a and E g y p t have devoted m u c h thought to the influence o f velocity, depth and other factors on the capacity of channels f o r maintening their depth and w i d t h , and also to the protection o f weirs, sluices, bridges and dams against scour. A characteristic o f the engineers engaged i n drainage and i r r i g a -tion projects i n these territories has been their tireless determina-tion to establish a scientific basis f o r the design of their works and a theory f o r the behaviour of waterways charged w i t h sand or silt. Sir Claude I N G L I S
P L A T E I Tlie main experimental hall at the Hydraulics Research .Station, Wallingford. (Photo: British Crown Copyright. Reproduced by kind permission of the Controller of H . M . Stationery Office and the Director of the Hydraulics Research Station - D.S.I.R.)
and M r . Gerald L A C E Y are notable l i v i n g members o f this b a n d o f enthusiasts.
Before securing its attractive site at WaUingford, the H y d r a u l i c s Research O r g a n i z a t i o n (as i t was then called) was granted space f o r a t i d a l model of the W y r e at the N a t i o n a l Physical L a b o r a t o r y , where some years previously Sir Thomas S T A N T O N (1865-1931) and M r . P A N N E L L h a d made their b e a u t i f u l experiments v e r i f y i n g the t r u t h o f the Reynolds n u m b e r as a criterion o f the resistance to flow i n " s m o o t h " pipes a n d investigating the effect o f the Reynolds number on the d i s t r i b u t i o n o f velocity across a diameter. T h e Hydraulics Research O r g a n i z a t i o n was also responsible f o r two models o f the Thames, w h i c h were accommodated i n premises owned by the Port o f L o n d o n A u t h o r i t y , f o r w h o m the investigations were undertaken. T h e smaller o f these models had hor-i z o n t a l and verthor-ical scales o f 1/3,000 and 1/60; hor-i t was hor-intended largely as a " p i l o t m o d e l " to assist i n the design o f the other, f o r w h i c h the scales were 1 /600 and 1 /60. I n sheer size, this represented a bold step i n British practice; the model was 400 feet (122 metres) long, as compared w i t h the 50 feet (15 metres) o f GIBSON'S Severn models (1926-1933) and the 125 feet (38 metres) o f the T a y t i d a l model (Dundee H a r b o u r T r u s t , 1947).
I t is interesting to note that long after its original purpose had been served, the smaller model o f the Thames was used f o r experiments con-cerned w i t h storm surges and the possibilities o f a surge-reducing barrage. T h e T a y model was recently revived to study the possible effects o f the piers o f the 41-span road bridge w h i c h is soon to be b u i l t between Dundee and the southern bank o f the F i r t h .
T h e m a i n experimental h a l l at the W a l l i n g f o r d Research Station n o w has a floor area o f about 170,000 sq.ft (15,800 sq.m). P L A T E I is a photo-graph o f the M a i n H a l l ; i n the left foreground is the serpent type wave generator f o r a new wave basin and the model shown i n the f o r e g r o u n d is o f Tauranga H a r b o u r i n N e w Zealand. T h i s model is equipped w i t h apparatus f o r reproducing waves, tides and t i d a l currents. A m o n g the other facilities (including channels and wave tanks and i n s t r u m e n t a t i o n and mechanisation sections) there is a recently installed current-iTieter r a t i n g tank 330 f t (100 m) long X 6 f t (1.83 m) wide x 7 f t (2.13 m ) deep, equipped w i t h a cable-driven carriage w h i c h runs o n overhead rails and whose speed, acceleration and deceleration can be regulated
f r o m a control room placed at one end o f the tank. T h e t o t a l staff o f the Station is approximately 210, compared w i t h 82 at the end o f 1953. A glance through the pages o f the annual Bulletins of the I n t e r n a t i o n a l Association f o r H y d r a u l i c Research, the publication o f w h i c h owed so m u c h i n former years to Professor THIJSSE, w i l l provide a good picture of the scope o f the investigations undertaken at W a l l i n g f o r d and o f the r a p i d g r o w t h of the Station. The activities have not been confined ex-clusively to the laboratory, but have also embraced interesting surveys and field studies on beaches and i n estuaries.
O f similar importance but i n the field o f solid-boundary hydraulics, i n c l u d i n g scale-model tests o f pumps, turbines and other machinery is the F l u i d Mechanics Division of the N a t i o n a l Engineering L a b o r a t o r y ,
PLATE I I The Reynolds Building of the National Engineering Laboratory, East K i l -bride, Glasgow. (Photo: British Crown Copyright. Reproduced by k i n d permission of the Controller of H . M . Stationery Office and the Director of the National Engineering Laboratory - D.S.I.R.)
P L A T E I I I Closed-circuit rig for testing pump models; National Engineering Labo-ratory. (Photo: British Grown Copyright. Reproduced by kind permission of the Con-troller of H . M . Stationery Office and the Director of the National Engineering Laboratory - D.S.I.R.)
situated at East K i l b r i d e , near Glasgow. This laboratory, under the direction of D r . D . G. S O P W I T H , F.R.S.E., is also Government-sponsored under the control of the Department of Scientific and I n d u s t r i a l Research, and is another post-World W a r I I creation, originally under the title o f the M e c h a n i c a l Engineering Research L a b o r a t o r y . P L A T E 2 shows the outside o f the h y d r a u l i c machinery b u i l d i n g , and P L A T E 3 the closed-circuit r i g f o r testing mixed-flow and centrifugal p u m p models of up to 300 horsepower. T h e laboratory has similar facilities f o r tests on water-turbine models and for aerodynamic experiments to determine design data f o r axial-flow turbo-machinery.
T h e British Hydromechanics Research Association, having its l a b o r a t o r y at H a r l o w , i n the county of Essex, about 25 miles n o r t h o f L o n d o n , is organized rather d i f f e r e n t l y : i t has been sponsored by i n d u s t r i a l and professional f i r m s w h i c h are concerned w i t h the manufacture and utilisa-t i o n of hydraulic equipmenutilisa-t b u utilisa-t i utilisa-t also receives an annual granutilisa-t o f money f r o m H e r Majesty's Treasury through the Department o f Scien-tific and I n d u s t r i a l Research. A l t h o u g h p r i m a r i l y concerned w i t h solid-boundary fluid mechanics, i t has carried out fascinating experiments o n the water-borne transportation of coal through pipes. I n a d d i t i o n to its laboratory activities, the laboratory (under the direction of M r . L . E . PROSSER) maintains an advisory and, as I am grateful to acknowledge, a most h e l p f u l l i b r a r y service.
Also operating on a national basis is the Research Station of the British Transport Docks Board, w h i c h is situated at Southall (Middlesex), 4 miles f r o m L o n d o n A i r p o r t . U n t i l recently, this Station ( D i r e c t o r : M r . J . T . EvANS, O.B.E.) was one of the research establishments o f the British Transport Commission, but its w o r k has always been concerned p r i -m a r i l y w i t h those docks, canals and i n l a n d waterways of ours w h i c h arc nationalised. I n terms o f space and number of Staff, i t is a small research laboratory by present-day standards b u t i t has been responsible for several valuable contributions to knowledge; for example an investiga-t i o n o f investiga-the possibiliinvestiga-ties of investiga-the pneumainvestiga-tic breakwainvestiga-ter (reporinvestiga-ted i n volume 231 (1955) of the Proceedings o f the R o y a l Society of L o n d o n ) . Recently, a m a j o r part of the effort of M r . E V A N S and his coUeagues has been devoted to the development of gauges for the continuous recording o f silt-concentration i n t i d a l waters. Fundamentally, these gauges, w h i c h are calibrated i n suspensions of k n o w n concentration, utilise the property of absorption o f light and the effect is registered i n the first place by a photo-electric cell whose reaction is transmitted electronically to a pen-recorder. Several o f these instruments have been installed i n the H u m b e r and the Severn estuaries and i t is hoped that i n time i t w i l l be possible to relate the operations to conditions of tides and other factors w h i c h affect the amount of silt appearing i n suspension at each particular place. A n immediate apphcation of this technique has been i n the investigation of certain problems associated w i t h the project (now being implemented) to i m p o u n d the K i n g George Dock at H u l l . For this i m p o u n d i n g scheme, water w i l l be pumped f r o m the t i d a l river and one of the questions has
been how m u c h sUt wiU be carried into the Dock and w i l l have to be dredged subsequently. T h e continuouslyrecording silt meters have p r o -vided useful i n f o r m a t i o n and have suggested what m i g h t be the most economic periods d u r i n g a tide for the p u m p i n g operation to be done, taking into account the expenditure involved i n the p u m p i n g against the variable heads and the q u a n t i t y of silt likely to be transferred to the Dock. Other aspects o f the project, such as the design of the intake, have been studied on models constructed to a scale of 1/16.
I should f u r t h e r mention that some manufacturers concerned w i t h valves and hydraulic machinery, and a few firms of consulting and of contracting c i v i l engineers have their o w n laboratories, and o f course the internationally recognised researches on tides and waves by Professor J . P R O U D -M A N , D r . A . T . DooDSON, Brigadier R. A . B A G N O L D and D r . -M . S. L O N G U E T - H I G G I N S (all Fellows o f the R o y a l Society of L o n d o n ) while not directly i n the field o f hydraulics nevertheless have great interest f o r maritime engineers.
I come next to the work of the Universities and the m a j o r T e c h n i c a l Colleges. I t cannot be said that their facilities for hydraulics have i m proved on a scale commensurate w i t h the national laboratories at W a U i n g -f o r d and East K i l b r i d e , or w i t h the more spectacular o-f the university ventures i n the realm o f radio-astronomy and nuclear physics. I n general, hydraulics is taught i n our departments o f civil and mechanical engi-neering, and though there is one Chair (occupied b y our distinguished colleague C. M . W H I T E at the I m p e r i a l College o f Science and Technol-ogy) specifically allotted to Hydraulics and F l u i d Mechanics, m u c h depends on the personal interest of the Professors i n charge o f the more general curricula. O n the whole, the tendency has been towards a degree of specialisation w h i c h d i d not apply i n the earlier days to w h i c h I referred at the beginning o f this essay, and i t is significant that the m a j o r i t y of our university chairs o f civil engineering to-day are held b y professors p r i m a r i l y interested i n structural engineering. I do not t h i n k i t is misleading to say that on the whole our laboratory facilities i n hydraulics have i m p r o v e d less than i n structural engineering. A h a p p y exception to this w i l l soon be evident i n D r . C. M . W H I T E ' S new labo-ratories at I m p e r i a l College. A g a i n , and I suppose this to be true i n the Netherlands and other countries as well, the g r o w t h i n the student-population and the demand for expansion have imposed an
administra-tive strain w l i i c l i apparently d i d not exist before 1939 - or is i t that the giants of the past were able to take that side o f their duties more l i g h t -heartedly i n their stride?
However, perhaps there is something i n the theory that an academie researcher could be too lavishly surrounded w i t h m a t e r i a l resources and that the g i f t of improvisation w h i c h was so skilfully exploited by men like R E Y N O L D S and GIBSON m i g h t wither i n easier circumstances. N a t -urally, the o v e r w h e l m i n g tendency is now f o r the investigation o f ad hoc problems r e q u i r i n g considerable floor-space and expensive testing devices to be entrusted to the large national laboratories and f o r the universities to concentrate on the particular studies whether basic or ad hoc -w h i c h can be done -w i t h the l i m i t e d provision of space, equipment and pei-sonnel at their c o m m a n d . Even i n recent years, however, there have been occasional exceptions to this, as i n the case o f the large t i d a l model of Southampton W a t e r (horizontal scale 1 / 1 2 5 0 and v e r t i c a l scale 1 / 1 0 0 ) sponsored by one of the o i l companies and b u i l t at S o u t h a m p t o n U n i v e r -sity by W . W R I G H T (now Professor at T r i n i t y College, D u b U n ) , w h i l e many projects r e q u i r i n g smaller models have been entrusted to various university laboratories. A m o n g these, mention may be made o f D r . R . B . W H I T T I N G T O N ' S w o r k at L i v e r p o o l o n the M i l f o r d H a v e n Project, w h i c h contemplates the construction of a barrage having sluice gates to be opened only d u r i n g the ebb tide so that the water i m p o u n d e d above the barrage w o u l d eventually become fresh and suitable as a source o f water supply.
O n the whole, the type of p r o b l e m best suited to the smaller university laboratories is represented by some o f the detailed features of water-supply and hydro-electric projects. T h e spillways of many of the post-war power schemes of the N o r t h of Scotland H y d r o - E l e c t r i c B o a r d have been designed w i t h the a i d o f laboratory experiments on models. O w i n g to the comparatively small and simple models involved i n these cases, a n d the v i t a l importance and heavy cost of the works themselves, this class of investigation can be economically attractive to a h i g h degree, and when done i n universities or technical colleges, they are an interesting and valuable practice f o r students. I t is h a p p i l y still possible, also, to find men like M r . A . M . B I N N I E , F . R . S . , of Cambridge, pursuing f u n d a -mental research ( i n his case o n subjects such as the s w i r l i n g flow of water i n a vertical pipe and a bend) w i t h simple apparatus a n d the g i f t o f
appreciating w i i a t can be seen by many b u t understood by few. A n d again, i t is sometimes practicable for our university men to f i n d a f r u i t -f u l co-operation w i t h industrial or pubhc Authorities. A notable example is the i n t r i g u i n g development of the thermodynamic method of meas-u r i n g the power-omeas-utpmeas-ut of water tmeas-urbines: D r . A . S. T H O M of Glasgow University has supervised studies i n this field, w h i c h is certainly basic as w e l l as applied research, and has had the o p p o r t u n i t y of testing equip-ment on full-scale plant i n Scottish hydro-electric power stations. Problems i n the hydraulics of sewerage are receiving m u c h attention, not only i n estabhshments of the Department of Scientific and I n d u s t r i a l Research (the Hydraulics Research Station, the Road Research L a b o -r a t o -r y and the Wate-r Pollution Resea-rch Labo-rato-ry) b u t also i n unive-r- univer-sities, p a r t i c u l a r l y B i r m i n g h a m , L o n d o n , Manchester and Sheffield. A report o f a Symposium on this subject appeared i n the Proceedings o f the I n s t i t u t i o n o f C i v i l Engineers i n December 1962, and I quote one paragraph to show that m u c h remains to be done:
" A n outstanding problem - i f not indeed a mystery - is that o f 'scale-effect' i n laboratory studies o f sedimentation tanks. Compar-isons between the behaviour of models of different scales and o f models w i t h full-size tanks had so far failed to elucidate the criteria for s i m i l a r i t y . "
I n the preceding pages, I have tried to indicate broadly w h a t is going on i n British hydraulics to-day and h o w the situation has developed. M u c h o f the stimulus has, of course, come n o m au appreciation of w h a t is being done, and how i t is being done, i n other countries. I fear that m y account is very inadequate b u t I w i l l venture to offer a few comments, w h i c h w i l l not necessarily secure general approval.
T h e scepticism towards research apparent i n many successful practising engineers of the 19th and early 20th century has v i r t u a l l y disappeared but i t w o u l d be w r o n g to ignore the fact that some of the doubters h a d other quahties of energy and initiative w h i c h are certainly needed i f the new attitude towards science is to be preserved and its results applied. T h e conviction has g r o w n " t h a t the expenditure i n Great B r i t a i n " ( I quote f r o m the first Buhetin, M a r c h 1963, of the C i v i l Engineering Research Council) " o n c i v i l engineering research was inadequate i n relation to needs, and the Advisory Council on Scientific Policy reported to the Government i n 1959 that there was indeed a serious deficiency i n
research and development over the whole field of civil engineering". W i t h a view to t r y i n g to remedy this situation, the I n s t i t u t i o n of C i v i l Engineers, the Federation o f C i v i l Engineering Contractors and the Association of Consulting Engineers conceived the f o r m a t i o n of a C i v i l Engineering Research Council, w h i c h does not at present intend to set up its o w n laboratories b u t to encourage the f u l l use of existing facilities and to give financial support to approved projects. I t remains to be seen how successful the new venture w i h be b u t i t is receiving or has been promised monetary support f r o m the I n s t i t u t i o n of C i v i l Engineers, f r o m a number of firms and f r o m the Department of Scientific and I n d u s t r i a l Research. Already some university researches are being supported by the Council. This is obviously splendid news and i t is to be hoped that those i n the universities anxious to avail themselves o f this new source of help w i l l be able to solve the other problems of finding time and personal assistance, i n c l u d i n g laboratory and workshop technicians.
I feel that the dangers of "dispersal and d u p l i c a t i o n of e f f o r t " are some-times exaggerated; i t can be reasonably argued that m a n y researchers w o r k i n g independently may produce a broad advance even though they started on the same p r o b l e m ; one person t r y i n g to answer a specific question often encounters an associated p r o b l e m w h i c h leads h i m to proceed along lines not originally contemplated.
Professor THIJSSE'S l o n g career has been concerned not only w i t h the p r o m o t i o n of knowledge by teaching and research b u t also w i t h the f o r m i d a b l e reaUties of m a j o r engineering works. I wonder whether he w o u l d agree w i t h me that progress has been slow i n laying d o w n rules for the choice of scales, especially where "loose b o u n d a r y " models are concerned. O n the constructional and operational side i n c l u d i n g instru-mentation, r a p i d advances have been achieved: examples w h i c h spring to m i n d are the design of wave and tide generators and the application of electronics to instruments f o r measuring small and fluctuating veloc-ities or waves of short p e r i o d ; even the use of transparent materials i n models of spillways, siphons and the hke has revolutionised laboratory practice by enabhng phenomena to be directly observed w h i c h previously had to be conjectured, sometimes speculatively, f r o m pressure and veloc-i t y probes alone. These are a l l veloc-invaluable means to end, b u t the p r o b l e m of "scale effect" is f a r f r o m being solved. I f we observe a vortex and entrainment of air i n a model of a pump-intake or a siphon spillway,
we must still exercise great caution i n interpreting its meaning w h e n translated to f u l l scale, and the question of the exaggeration of the vertical scale of river models is always w i t h us. I t appears to be axiomatic that the larger the horizontal dimensions of a given river model, the smaller its vertical exaggeration can or should be made. M r . Gerald L A C E Y has f o r m u l a t e d a quantitative relationship f o r this phenomenon; i n its latest f o r m (1958) his theory implies that one and the same exaggeration cannot be equally suitable over the whole area of a tidal m o d e l ; i t w i U tend to be too large for the wide, seaward p o r t i o n i f i t is correct f o r the n a r r o w upper reaches.
I conclude by suggesting that there should be a mass attack on this p r o b l e m of scale effect. T h e great variety of scales adopted i n British practice is revealed by the f o l l o w i n g table of some examples:
M o d e l
Mersey (O. REYNOLDS) (circa 1887)
Severn (A. H . GIBSON) *
Mersey and Liverpool Bay (A. H . GIBSON) Parrett (A. H . GIBSON) *
Cheshire Dee (A. H . GIBSON) * G u l f of Martaban and Rangoon River (Sir Alexander G I B B and Partners) * Wash and River Great Ouse
(Great Ouse River Board) *
Tay (Dundee Harbour Trust) ** Thames (Sir Claude INGLIS) **
Pilot model M a i n model
Trent (Sir Claude INGLIS) **
K a r n a f u l i River (Sir Claude INGLIS) ** Southampton Water (W. W R I G H T ) **
* Period 1926-1939 ** Since 1945.
Horizontal Vertical Vertical
scale scale exaggeration
1/31800 1/960 33. 1/10560 1/396 26.7 1/8500 1/100 85. 1/200 42.5 1/7040 1/190 37, 1/3000 1/260 11.5 1/5000 1/200 25. 1 /4ÜÜ00 1/400 100. 1/8060 1/192 42. 1/2500 1/60 41.7 1/1760 1/144 12.2 1/3000 1/120 25. 1/600 1/60 10. 1/800 1/72 11.1 1/500 1/60 8.33 1/1250 1/100 12.5
The only definite conclusion to be derived f r o m the tabulated data is that exaggerations of scale are generally smaller i n the post-war period, w h i c h happens to coincide w i t h the availabihty of better facilities and larger floor areas.
Nor can i t be properly claimed that any of our investigations of the influence of grain-size and density on the conclusions obtained f r o m river models have carried us f u r t h e r than GIBSON'S tests ( 1 9 2 6 - 1 9 3 3 ) on sands, pumice and powdered emery, f r o m w h i c h he felt that a sand having a grain size about three-quarters of the n a t u r a l sand behaved as well as or better than other materials.
I have long been convinced that time, money and skilled observers w o u l d be well employed i n repeating some of the well-documented investiga-tions, using different scales, and i n t r y i n g to collect refiable i n f o r m a t i o n on how far the model indications have been verified i n N a t u r e . As m y respected professor, GIBSON, once w r o t e :
"the final answer to the question (of reUabifity) can only be given when we have available the results of many model tests and cor-responding results under similar conditions i n nature, and u n t i l then caution must be used i n predicting quantitative results."
