1. What is Mach Number?

Definition: The Mach number is a dimensionless quantity representing the ratio of flow velocity to the local speed of sound.

Purpose: It's used in aerodynamics to characterize different flow regimes (subsonic, transonic, supersonic, hypersonic).

2. How is Mach Number Calculated?

The calculator uses the formula:

Where:

• \( M \) — Mach number (dimensionless)
• \( V \) — Flow velocity (m/s)
• \( \gamma \) — Ratio of specific heats (1.4 for air)
• \( R \) — Specific gas constant (287 J/kg·K for air)
• \( T \) — Absolute temperature (K)

Explanation: The Mach number compares the object's speed to the speed of sound in the surrounding medium.

3. Importance of Mach Number

Details: Critical for aircraft design, predicting shock waves, compressibility effects, and aerodynamic heating.

4. Using the Calculator

Tips: Enter velocity in m/s, γ (default 1.4 for air), R (default 287 J/kg·K for air), and temperature in Kelvin. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What does Mach 1 mean?
A: Mach 1 means the object is traveling at the speed of sound in the current medium (about 343 m/s in air at 20°C).

Q2: Why is temperature important in Mach calculation?
A: The speed of sound varies with temperature, so Mach number depends on both velocity and environmental conditions.

Q3: What's a typical γ value for air?
A: For dry air at standard conditions, γ (gamma) is approximately 1.4.

Q4: How does altitude affect Mach number?
A: Higher altitudes have lower temperatures, which decreases the speed of sound, increasing Mach number for the same velocity.

Q5: What are the different Mach regimes?
A: Subsonic (M < 0.8), Transonic (0.8 < M < 1.2), Supersonic (1.2 < M < 5), Hypersonic (M > 5).