4

2nd YEAR FLUIDS / COMPRESSIBLE FLOW

 

- CONSIDER A WEAK WAVE, TRAVELLING IN A STAGNANT FLUID, AT VELOCITY C, RAISING THE PRESSURE, DENSITY TEMPERATURE AND VELOCITY BY P, T, AND U.





- THIS IS EQUIVALENT TO A STATIONARY WAVE IN A FLUID MOVING AT VELOCITY C.



 

FROM CONTINUITY

r A C = ( r + Dr ) A ( C - DU )





- NOTE THAT DU << C      SINCE    Dr << ( r + Dr )