1. What is Mach Number?

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

Purpose: It's used in aerodynamics to compare aircraft speeds to the speed of sound and classify different flight regimes.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( M \) — Mach number (dimensionless)
• \( V \) — Velocity of the object (m/s)
• \( a \) — Speed of sound in the medium (m/s)

Explanation: The Mach number indicates how many times faster the object is moving compared to the speed of sound in that medium.

3. Importance of Mach Number

Details: Mach number is crucial in aerodynamics for:

• Determining compressibility effects
• Classifying flight regimes (subsonic, transonic, supersonic, hypersonic)
• Designing aircraft and propulsion systems
• Predicting shock wave formation

4. Using the Calculator

Tips:

• Enter the object's velocity in m/s
• Enter the speed of sound in the medium (default 343 m/s for air at 20°C)
• All values must be positive numbers

5. Frequently Asked Questions (FAQ)

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

Q2: How does temperature affect Mach number?
A: The speed of sound increases with temperature, so the same velocity will result in a lower Mach number at higher temperatures.

Q3: What's the typical speed of sound in air?
A: Approximately 343 m/s at 20°C (68°F), but it varies with temperature (331 m/s at 0°C).

Q4: 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).

Q5: Can Mach number be greater than 1?
A: Yes, Mach numbers greater than 1 indicate supersonic speeds where shock waves form.