Linearized velocity potential equation is valid for

• transonic flow

• hypersonic flow

• subsonic and supersonic flows

• all types of flows

For small disturbances in a stationary gas, and for flows where the velocity deviates only slightly from a parallel uniform flow, the method of ____ may be employed for linearizing the governing equations.

• characteristics

• small perturbations

• velocity potential

• none of the above

Pick out the wrong statement

• In subsonic flow, Gothert rule provides the comparison of performance between bodies placed in compressible and incompressible flows

• Prandtl Glauert rule permits the comparison between bodies placed in compressible and incompressible flows

• both the above statements

• none of the above statements

Using Prandtl Glauert rule, the relation between C_L in compressible flow and that in incompressible flow is given as

In a geometrical transformation, if all coordinates in a given direction are changed by a uniform ratio, then the transformation is called ______.

The linearized velocity potential equation is _____ for M_∞< 1.

• elliptic

• parabolic

• hyperbolic

• none of the above

The linearized velocity potential equation is _____ for M_∞ > 1.

The small perturbation equations for subsonic and supersonic flows are _____, and for transonic flows the equation is _____.

• linear, non-linear

• non-linear, linear

• linear, linear

• non-linear, non-linear

The small perturbation potential flow equations cannot be used for

• rockets

• missiles

• aerofoils

• none of the above