May, 1948.] Criterion for Scaling Model Experiments. 161 



required to follow rather impractical scaling laws, but by assuming that 

 their influence on the flow is unimportant in a certain range of velocities, 

 a solution is obtained by omitting them from further consideration. 

 The dependence of the variables is expressed in terms of the exponent 

 bi'^ in the expression 





(5.2) 



where x' is the appropriate value of the it\\ variable on any scale with 

 a typical length R related to the model scale with corresponding values 

 x*° and R°. The computation of the bi'^ requires only the determination 

 of that row of A r' which corresponds to the column of .^4 1 in which R 

 appears. 



REFERENCES. 



(1) H. L. Langhaar, Journal Franklin Inst., Vol. 242, p. 459 (1946). 



(2) E. Buckingham, Phys. Rev., Vol. 4, p. 345 (1914). 



(3) P. Bridgman, "Dimensional Analysis," Yale University Press, 1922. 



(4) G. BiRKHOFF AND S. MacLane, "A Survey of Modern Algebra," Macmillan, 1944. 



