16
2nd YEAR FLUIDS / COMPRESSIBLE FLOW
3
NOW FOR COMPRESSIBLE FLOW, CONSIDER A RESERVOIR, CONTAINING COMPRESSED GAS AT STAGNATION CONDITIONS O, PO AND TO, WHICH EXPANDS INTO AN INFINITE ATMOSPHERE OF PRESSURE PA, THROUGH A VARIABLE-AREA DUCT.
FROM EQUATIONS (3.17) AND (3.18) :
- THE REDUCTION IN IS CRUCIAL BECAUSE IT LEADS TO A MUCH GREATER ACCELERATION THAN WOULD OCCUR FOR A CONSTANT DENSITY FLOW.
- FROM CONTINUITY (3.25) :
