10 



0-6 



°/ 



'\ 06 



7 h o-4 



MAX. 

 0-2 



10" 



20" 



30" 



40" 



50° 



60° 



9 



Figure 10. Velocity and laminar wail shear stress distribution for Brodetsky flow past circular cylinder. 



true conditions of flow near the singularities even using a fine network near these 

 points. 



Professor Garrett Birkhoff and his colleagues (1953) have used computer 

 techniques extensively on plane flow problems with curved profiles: they have in fact 

 extended the Brodetsky approach to cavity flow to a much higher degree of refine- 

 ment. Their investigations have given valuable experience of the formulation of 

 plane flow problems and should prove of considerable value when the physical condi- 

 tions of flow in the neighbourhood of the separation point are better understood. 



These difficulties are no longer present if separation is defined by a corner, as 

 for instance in the flow past wedges and discs. Although the singularity of the flow 

 still exists at the corner in these cases, its behaviour is well understood and can be 

 allowed for. The velocity distribution for abrupt separation at a corner can be seen 

 in Fig. 1 1 and may be compared with that for smooth separation with a curved 

 profile as shown in Fig. 10. 



M. S. Plesset and P. A. Schaffer (1948) calculated the drag coefficients for 

 a series of cones and discs over a range of cavitation numbers using the assumption 

 that the pressure distribution along the generator of the cone or disc was the same 

 as that on a wedge having the same semi-angle at the same cavitation number. The 

 implications of this assumption have been investigated more recently by Armstrong 

 (1953(a)) who, as a result, proposed improved similitude rules for wedges and cones. 

 Armstrong showed that, if the velocity distributions near the apex of a wedge (semi- 



12> 



