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Statement (I) : When a bluff body moves at supersonic speed in still air, an attached shock wave is produced at its nose causing the flow to be subsonic behind the shock plane. Statement (II) : A normal shock always transforms supersonic flow into subsonic flow causing increase in pressure, temperature and entropy.

Statement (I) : When a bluff body moves at supersonic speed in still air, an attached shock wave is produced at its nose causing the flow to be subsonic behind the shock plane. Statement (II) : A normal shock always transforms supersonic flow into subsonic flow causing increase in pressure, temperature and entropy. Correct Answer Both Statement (I) and Statement (II) are individually true and Statement (II) is NOT the correct explanation of Statement (I)

Concept:

Consider flow near front of bluff body placed in supersonic flow as shown in figure,

→ The shock wave ahead of body is curved in general but ahead of very front of body, the shock is effectively normal to flow

→ since, the flow downstream is normal shock wave is always subsonic, the deceleration from point 2 to point 3 is figure can reduce velocity effectively to zero.

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