348 



TABLE 345.— COMPRESSIBLE FLOW TABLES FOR AIR 1 " 



In high speed research, use is frequently made of the theoretical relationships existing 

 between the Mach number and various flow parameters. Two types of flow are tabulated : 

 isentropic flow and normal-shock flow. Isentropic flow is generally valid for a subsonic or 

 supersonic expanding flow and may be used for subsonic compression flow. Normal-shock 

 How is valid for supersonic compression flow when the deviation of the flow through the 

 shock is zero. Oblique-shock flow may be obtained from the normal-shock flow by super- 

 imposing a velocity tangential to the shock. Mm . . 



The assumption that air is a perfect gas with a value of 7 of 1.400 is valid tor the condi- 

 tions usually encountered in the subsonic and lower supersonic regions for normal stagna- 

 tion conditions. For Mach numbers greater than about 4.0 or for unusual stagnation 

 conditions, however, the behavior of air will depart appreciably from that of a perfect gas 

 if the liquefaction condition is approached, and caution should be used in applying the 

 results in the table at the higher Mach numbers. 



The formulas for isentropic flow are: 



\ 



1 + 



il/a 2 ) ' 





7 + 1 

 2 (7-D 



1 + 



Mr, 





Fc = 



7M,* 



( 



1 + 



T-l 



M.f 1 '-^ 



* = sin "' (w) 



, = (z+j)' C05 -.r 7+1 T + » 



90°. 



and the formulas for normal-shock flow are 



P2 _ 27 



Pi 



Mr - 



7-1 



7 + 1 ' 7 + 1 



h - (h\(h\ 



po \pJ\Po) 



po \P2J\P0J 



«• Burcher. Marie A., Compressible flow tables for air, NACA TN No. 1592, August 1948. 



(continued) 



SMITHSONIAN PHYSICAL TABLES 



