Pritchard, W. G.
Overview
Works:  25 works in 44 publications in 1 language and 56 library holdings 

Genres:  Academic theses 
Roles:  Author 
Classifications:  QA927, 
Publication Timeline
.
Most widely held works by
W. G Pritchard
An evaluation of a model equation for water waves by
J. L Bona(
Book
)
3 editions published in 1981 in English and held by 10 WorldCat member libraries worldwide
3 editions published in 1981 in English and held by 10 WorldCat member libraries worldwide
Experiments on wave trapping by a submerged cylindrical island by
United States(
Book
)
4 editions published in 1982 in English and Undetermined and held by 5 WorldCat member libraries worldwide
A description is given of some experiments made to examine the possible trapping of surface waves by a submerged cylindrical sill in an otherwise uniform ocean. Theories by LonguetHiggins (1967) and Renardy (1981) indicate that, at certain dangerous frequencies, nearly resonant conditions may obtain, leading to unusually large wavefields over the sill. These resonances have been sought experimentally by examining two functionals of the wavefield over the sill to see if they should become unusually large near certain of the dangerous frequencies. The results show no manifestation whatsoever of the resonances. Possible reasons for the discrepancies are considered. It has, however, been observed that, at certain locations over the sill, the waves were amplified by a factor of four or five times their magnitude in the 'ocean', irrespective of the frequency in a certain interval. This could be an important consideration for the siting of rigs on prominent topographic features of the ocean bed
4 editions published in 1982 in English and Undetermined and held by 5 WorldCat member libraries worldwide
A description is given of some experiments made to examine the possible trapping of surface waves by a submerged cylindrical sill in an otherwise uniform ocean. Theories by LonguetHiggins (1967) and Renardy (1981) indicate that, at certain dangerous frequencies, nearly resonant conditions may obtain, leading to unusually large wavefields over the sill. These resonances have been sought experimentally by examining two functionals of the wavefield over the sill to see if they should become unusually large near certain of the dangerous frequencies. The results show no manifestation whatsoever of the resonances. Possible reasons for the discrepancies are considered. It has, however, been observed that, at certain locations over the sill, the waves were amplified by a factor of four or five times their magnitude in the 'ocean', irrespective of the frequency in a certain interval. This could be an important consideration for the siting of rigs on prominent topographic features of the ocean bed
A comparison of solutions of two model equations for long waves by
United States(
Book
)
4 editions published in 1983 in English and Undetermined and held by 5 WorldCat member libraries worldwide
This paper is concerned with mathematical models representing the unidirectional propagation of weakly nonlinear dispersive waves. Interest will be directed toward two particular models that are originally studied in the context of surfacewave phenomena in openchannel flows. The purpose of the present paper is to make a quantitative comparison between the solutions to the initialvalue problem for each of these models. The basic conclusion of the study is that, on a long time scale T naturally related to the underlying physical situation, the equations predict the same outcome to within their implied order of accuracy. In this case the choice of one of these models over the other to describe a physical problem is apparently immaterial, with factors of incidental convenience probably providing the main criteria in a given situation. (Author)
4 editions published in 1983 in English and Undetermined and held by 5 WorldCat member libraries worldwide
This paper is concerned with mathematical models representing the unidirectional propagation of weakly nonlinear dispersive waves. Interest will be directed toward two particular models that are originally studied in the context of surfacewave phenomena in openchannel flows. The purpose of the present paper is to make a quantitative comparison between the solutions to the initialvalue problem for each of these models. The basic conclusion of the study is that, on a long time scale T naturally related to the underlying physical situation, the equations predict the same outcome to within their implied order of accuracy. In this case the choice of one of these models over the other to describe a physical problem is apparently immaterial, with factors of incidental convenience probably providing the main criteria in a given situation. (Author)
Numerical schemes for a model for nonlinear dispersive waves by
J. L Bona(
Book
)
4 editions published in 1983 in English and Undetermined and held by 5 WorldCat member libraries worldwide
A description is given of a number of numerical schemes to solve an evolution equation (KortewegdeVries) that arises when modelling the propagation of water waves in a channel. The discussion also includes the results of numerical experiments made with each of the schemes. It is suggested, on the basis of these experiments, that one of the schemes may have (discrete) solitarywave solutions. (Author)
4 editions published in 1983 in English and Undetermined and held by 5 WorldCat member libraries worldwide
A description is given of a number of numerical schemes to solve an evolution equation (KortewegdeVries) that arises when modelling the propagation of water waves in a channel. The discussion also includes the results of numerical experiments made with each of the schemes. It is suggested, on the basis of these experiments, that one of the schemes may have (discrete) solitarywave solutions. (Author)
Instability and Chaotic Behaviour in a FreeSurface Flow by
Mathematics Research Center (United States. Army)(
Book
)
5 editions published between 1985 and 1986 in English and Undetermined and held by 4 WorldCat member libraries worldwide
This paper describes some experimental observations of freesurface flows arising when fluid poured over the end of a flat plate into a reservoir well below the plate. This class of flows was found to be highly unstable with over seven hundred qualitatively different flows being observed in the experiment. At very small values of the flux the liquid fell from the plate into the reservoir in the form of droplets which developed periodically at a number of sites on the underside of the plate. As the flux was increased these 'sites' were able to sustain continuous, unbroken streams and combinations of drip sites and continuous streams were possible. At still larger values of the flux there was a tendency for the liquid to fall in 'sheets' and several combinations of 'sheet flows' and continuous streams were observed, some of which flows exhibited a rather chaotic temporal behavior. At even larger flux values the flow resembled that of the classic waterfall, but here there were also some unexpected instabilities where the attachment line of the free surface of the liquid with the plate developed corrugations. Keywords: Hydrodynamic stability; Chaotic behaviour; Freesurface flows
5 editions published between 1985 and 1986 in English and Undetermined and held by 4 WorldCat member libraries worldwide
This paper describes some experimental observations of freesurface flows arising when fluid poured over the end of a flat plate into a reservoir well below the plate. This class of flows was found to be highly unstable with over seven hundred qualitatively different flows being observed in the experiment. At very small values of the flux the liquid fell from the plate into the reservoir in the form of droplets which developed periodically at a number of sites on the underside of the plate. As the flux was increased these 'sites' were able to sustain continuous, unbroken streams and combinations of drip sites and continuous streams were possible. At still larger values of the flux there was a tendency for the liquid to fall in 'sheets' and several combinations of 'sheet flows' and continuous streams were observed, some of which flows exhibited a rather chaotic temporal behavior. At even larger flux values the flow resembled that of the classic waterfall, but here there were also some unexpected instabilities where the attachment line of the free surface of the liquid with the plate developed corrugations. Keywords: Hydrodynamic stability; Chaotic behaviour; Freesurface flows
Reflection of Water Waves in a Channel with Corrugated Beds by
T. B Benjamin(
Book
)
4 editions published in 1987 in English and Undetermined and held by 4 WorldCat member libraries worldwide
Intended as a contribution towards understanding the multiple processes entailed in the development of coastal sand bars due to wave action, this theoretical and experimental study deals with the Bragg reflection of longcrested surface waves in a water channel whose bed is corrugated sinusoidally. The present findings complement and in a few respects improve upon those in previous investigations, particularly Davies and Heathershaw (1984). In chapter 2 a linearized theory is presented, being directed to the elucidation of experimental situations where monochromatic waves propagates into a channel with a limited stretch of corrugations on its bed and an imperfectly absorbing beach at its far end. Allowance is made fully for dispersive effect and approximately for small frictional effect. Points of interpretation include accounts of degenerate but nontrivial solutions that apply at frequencies terminating at the stopping band, wherein the spatial wavefield has an exponential envelope. The experimental results presented in chapter 4 derive from measurements of the wavefield over a stretch of 24 corrugations, at various frequencies both outside the stopping band. Quantitative comparisons demonstrate close agreements with the theory. Keywords: Water waves; Sand bars
4 editions published in 1987 in English and Undetermined and held by 4 WorldCat member libraries worldwide
Intended as a contribution towards understanding the multiple processes entailed in the development of coastal sand bars due to wave action, this theoretical and experimental study deals with the Bragg reflection of longcrested surface waves in a water channel whose bed is corrugated sinusoidally. The present findings complement and in a few respects improve upon those in previous investigations, particularly Davies and Heathershaw (1984). In chapter 2 a linearized theory is presented, being directed to the elucidation of experimental situations where monochromatic waves propagates into a channel with a limited stretch of corrugations on its bed and an imperfectly absorbing beach at its far end. Allowance is made fully for dispersive effect and approximately for small frictional effect. Points of interpretation include accounts of degenerate but nontrivial solutions that apply at frequencies terminating at the stopping band, wherein the spatial wavefield has an exponential envelope. The experimental results presented in chapter 4 derive from measurements of the wavefield over a stretch of 24 corrugations, at various frequencies both outside the stopping band. Quantitative comparisons demonstrate close agreements with the theory. Keywords: Water waves; Sand bars
Drag reduction arising from adhesive tapes by Brian John Silvester Barnard(
Book
)
2 editions published in 1971 in English and held by 3 WorldCat member libraries worldwide
2 editions published in 1971 in English and held by 3 WorldCat member libraries worldwide
The motion generated by a body moving through a stratified fluid at large Richardson numbers by Brian John Silvester Barnard(
Book
)
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
An electricallydriven instability in elastic liquids by Brian John Silvester Barnard(
Book
)
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
Cross waves II; experiments by Brian John Silvester Barnard(
Book
)
1 edition published in 1971 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 1971 in English and held by 2 WorldCat member libraries worldwide
Measurements of the viscometric functions for a fluid in steady shear flows by W. G Pritchard(
Book
)
1 edition published in 1971 in English and held by 1 WorldCat member library worldwide
1 edition published in 1971 in English and held by 1 WorldCat member library worldwide
A study of wave motions in rotating fluids by W. G Pritchard(
)
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
1 edition published in 1968 in English and held by 1 WorldCat member library worldwide
Bounds for surface solitary waves by
Grant Keady(
Book
)
1 edition published in 1973 in English and held by 1 WorldCat member library worldwide
1 edition published in 1973 in English and held by 1 WorldCat member library worldwide
An electricallydriven instability in elastic liquids by B. J. S Bamard(
Book
)
1 edition published in 1974 in English and held by 1 WorldCat member library worldwide
1 edition published in 1974 in English and held by 1 WorldCat member library worldwide
The excitation of surface waves near a cuttoff frequency by B. J. S Barnard(
Book
)
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
Cross waves II Experiments by B. J. S Bamard(
Book
)
1 edition published in 1971 in English and held by 1 WorldCat member library worldwide
1 edition published in 1971 in English and held by 1 WorldCat member library worldwide
The excitation of surface waves near a cutoff frequency by B. J. S Barnard(
Book
)
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
Withdrawal from a reservoir of stratified fluid by
John J Mahony(
Book
)
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
1 edition published in 1977 in English and held by 1 WorldCat member library worldwide
Wave reflection from beaches by
John J Mahony(
Book
)
1 edition published in 1978 in English and held by 1 WorldCat member library worldwide
1 edition published in 1978 in English and held by 1 WorldCat member library worldwide
A Free Boundary Problem in Newtonian Flow(
Book
)
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
The construction of a computer program or code to solve steady free surface flows with surface tension at small Reynolds numbers is described. The code uses fixedpoint iteration for the nonlinearities in the NavierStokes equations and a secondorder finite element scheme. Before using the code on general flow problems such as coating flows, it is necessary to test it as throughly and rigorously as possible. Numerical tests for such a code are usually only done against a previously computed approximate solution to the drivencavity flow. However, the authors have instead chosen to test their code against three flows for which exact solutions are known: the CouettePoiseuille flow, the JeffreyHamel flow and Richardson's stickslip flow. Convergence tests are presented. (Author)
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
The construction of a computer program or code to solve steady free surface flows with surface tension at small Reynolds numbers is described. The code uses fixedpoint iteration for the nonlinearities in the NavierStokes equations and a secondorder finite element scheme. Before using the code on general flow problems such as coating flows, it is necessary to test it as throughly and rigorously as possible. Numerical tests for such a code are usually only done against a previously computed approximate solution to the drivencavity flow. However, the authors have instead chosen to test their code against three flows for which exact solutions are known: the CouettePoiseuille flow, the JeffreyHamel flow and Richardson's stickslip flow. Convergence tests are presented. (Author)
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