Hydrodynamic Problems Solved by Rheoelectric Analogies 



5UPERCAVITATING HYDROFOIL 



a-0 , f=i 



Fig. 10 - Comparison of foils of different linear pressure distributions 

 with a foil fulfilling the two-term law of Tulin-Burkart 



foils. It is known that near the leading edge of a hydrofoil, if the slope is finite 

 at the lower surface and the pressure constant at the upper surface, the com- 

 plex perturbation potential + iv^ gives a singularity of -ikz^/'' which corre- 

 sponds to a complex perturbation velocity u - iv = - ikz"^"*. The pattern of the 

 singularity is given in Fig. 12a, where it is seen that the equipotential line from 

 the upper surface of the slit is bending in the leading edge, forming an angle of 

 240°. Analogically this can be obtained by means of an apparatus shown in the 

 Fig. 12b. The electrode representing the upper surface of the cavity is extended 

 by a small conductor plate placed at an angle of 240°. In the prolongation of this 

 plate a probe is installed, by means of which the correct configuration of the 

 equipotential line can be controlled by adjustment from the potentiometer. 



This setup is successful only in two-dimensional problems. It cannot be 

 used in three-dimensional situations because of the complexity encountered. 



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