यदि किसी तरल का घनत्व पूरे आयतन में स्थिर रहता है, तो इसका तात्पर्य किस प्रकार के प्रवाह से है?

Which equation represents the steady 1D continuity equation for a compressible fluid flow?

In a steady fluid flow, the velocity of the fluid at any given point:

Which of the following expressions represents a possible stream function (Ψ) for a two-dimensional incompressible flow?