Figure J 9. Twin hollow core vortex-tubes at rear of steady cavity. 



Similar remarks can be made concerning conditions governing cavity closure. 

 The principles involved in both surface closure and deep seal are now fairly well 

 understood from war-time researches; there is, however, still scope for the develop- 

 ment of improved theoretical techniques which would enable these features to be fol- 

 lowed in greater detail. 



As regards cavity breakdown, and the subsequent entrainment of the air within 

 the cavity, the recent development of a theory which explains the effect of buoyancy 

 on the generation of twin, hollow core, vortices at the rear end of the cavity is prob- 

 ably capable of theoretical extension. 



BIBLIOGRAPHY 



Armstrong, A. H. and Miss J. H. Dunham (1953). 

 Axi-symmetric Cavity Flow. 



Ministry of Supply, A.R.E. Report 12/53. 



Armstrong, A. H. [1953(a)]. 



Drag Coefficients of Wedges and Cones in Cavity Flow. 

 Ministry of Supply, A.R.E. Report 21/54. 



Armstrong, A. H. [1953 (b)]. 



Abrupt and Smooth Separation in Plane and Axi-symmetric Cavity Flow. 

 Ministry of Supply, A.R.E. Memorandum 22/53. 



Armstrong, A. H. and K. G. Tadman (1954). 

 Axi-symmetric Cavity Flow about Ellipsoids 



Ministry of Supply, A.R.E., Theoretical Research Memorandum 5/54. 



Birkhoff, Garrett (1950). 



Hydrodynamics: a Study in Logic, Fact and Similitude. 

 Princeton University Press, 1950. 



Birkhoff, Young and Zarantonello (1953). 



Proc. Symposium on Applied Mathematics, 4, 117-140, 1953. 



Brodetsky, S. (1922). 



Discontinuous Fluid Motion Past Circular and Elliptic Cylinders. 

 Proc. Roy. Soc. (A), 102, p. 542, 1923. 



Coombs, A. (1956). 



The Oblique Water Entry of a Cone. 



A.R.D.E. Publication in preparation. 



Cox, A. D. and W. A. Clayden (1956). 



Cavitating flow about a Wedge at Incidence. 



Ministry of Supply, A.R.D.E. Report (B) 3/56. 



232 



