1. What is Mach Number?

The Mach number is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is a critical parameter in compressible aerodynamics that characterizes flow regimes from subsonic to hypersonic.

2. How Does the Calculator Work?

The calculator uses the fundamental Mach number equation:

Where:

• \( M \) — Mach number (dimensionless)
• \( v \) — Flow velocity (m/s)
• \( a \) — Local speed of sound (m/s)

Explanation: The Mach number quantifies compressibility effects in fluid flow, with different flow regimes defined by specific Mach number ranges.

3. Importance of Mach Number Calculation

Details: Mach number calculation is essential for aircraft design, rocket propulsion, wind tunnel testing, and understanding compressible flow phenomena like shock waves and expansion fans.

4. Using the Calculator

Tips: Enter velocity and speed of sound in meters per second (m/s). Both values must be positive and non-zero. The speed of sound varies with temperature and altitude in atmospheric applications.

5. Frequently Asked Questions (FAQ)

Q1: What are the different Mach number regimes?
A: Subsonic (M < 0.8), Transonic (0.8 ≤ M ≤ 1.2), Supersonic (1.2 < M ≤ 5.0), Hypersonic (M > 5.0).

Q2: How does speed of sound vary with temperature?
A: For air, speed of sound \( a = \sqrt{\gamma R T} \), where γ=1.4, R=287 J/kg·K, T=temperature in Kelvin.

Q3: Why is Mach number important in aircraft design?
A: It determines critical design aspects like wing shape, engine requirements, and structural considerations due to compressibility effects.

Q4: What happens when Mach number exceeds 1?
A: Shock waves form, creating sudden changes in pressure, temperature, and density, significantly affecting aerodynamic performance.

Q5: Can Mach number be less than 0?
A: No, Mach number is always positive as it represents the ratio of two positive quantities (velocity and speed of sound).