Compressible Flow – Definition of Stagnation Point In a compressible flow field, any point where the local fluid velocity reduces to zero relative to the body (for example, at the nose of a blunt object) is known as the stagnation point.

Introduction:
Flow nomenclature distinguishes special points that control pressure and temperature fields. The stagnation point is central in aerodynamics and turbomachinery because it ties measured stagnation (total) properties to local flow behavior.

Given Data / Assumptions:

• Steady compressible flow past a body.
• Reference frame attached to the body; local speed may fall to zero.
• Negligible viscous heating in the free stream.

Concept / Approach:

At a stagnation point, velocity V = 0, so static pressure attains a local maximum on the surface (stagnation pressure for inviscid assumptions). Total enthalpy relates stagnation temperature and static temperature via standard compressible relationships along streamlines absent losses.

Step-by-Step Solution:

Verification / Alternative check:

Pressure taps at a sphere’s front face register the highest static pressure where the local velocity is zero, confirming the stagnation-point definition.

Why Other Options Are Wrong:

Critical point: Refers to Mach 1 condition or mathematical criticality, not necessarily V = 0. Vena contracta: Minimum jet section downstream of an orifice. None of these: Incorrect since the standard term exists. Sonic point: Where M = 1, not V = 0.

Common Pitfalls:

Confusing stagnation with sonic conditions; ignoring viscous effects near walls that modify but do not change the V = 0 definition at the exact stagnation point.

Final Answer:

stagnation point