1. What is the Mach Number?

Definition: The Mach number is a dimensionless quantity representing the ratio of an object's speed to the speed of sound in the surrounding medium.

Purpose: It's used in aerodynamics to classify flow regimes and determine compressibility effects on aircraft and other high-speed objects.

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: Different Mach number ranges indicate different flow regimes:

• Subsonic (M < 0.8)
• Transonic (0.8 < M < 1.2)
• Supersonic (1.2 < M < 5)
• Hypersonic (M > 5)

4. Using the Calculator

Tips: Enter the object's velocity in m/s and the speed of sound in the medium (default 343 m/s for air at 20°C). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the speed of sound in air?
A: Approximately 343 m/s at 20°C (68°F), but varies with temperature (331 m/s at 0°C).

Q2: What does Mach 1 mean?
A: Mach 1 means the object is traveling exactly at the speed of sound in that medium.

Q3: How does altitude affect Mach number?
A: Higher altitudes have lower speed of sound due to colder temperatures, so the same true airspeed results in a higher Mach number.

Q4: What's the difference between indicated and true Mach number?
A: Indicated Mach number uses local speed of sound, while true Mach number uses standard conditions.

Q5: Why is Mach number important in aviation?
A: Critical for understanding compressibility effects, shock waves, and aircraft performance at high speeds.