1. What is a Normal Shock Relations Calculator?

Definition: This calculator computes the pressure ratio across a normal shock wave based on the specific heat ratio and upstream Mach number.

Purpose: It helps aerodynamics engineers and students analyze shock wave phenomena in compressible flows.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \frac{P_2}{P_1} \) — Pressure ratio across the shock (dimensionless)
• \( \gamma \) — Specific heat ratio (dimensionless, ~1.4 for air)
• \( M_1 \) — Upstream Mach number (dimensionless, must be ≥1)

Explanation: The formula relates the pressure increase across a normal shock wave to the incoming flow's Mach number and the fluid's thermodynamic properties.

3. Importance of Normal Shock Calculations

Details: Understanding shock waves is crucial for designing supersonic aircraft, jet engines, and other high-speed aerodynamic systems.

4. Using the Calculator

Tips: Enter the specific heat ratio (default 1.4 for air) and upstream Mach number (must be ≥1). All values must be valid for shock waves.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal shock wave?
A: A normal shock is a sudden, nearly discontinuous change in flow properties that occurs when supersonic flow is forced to decelerate to subsonic speeds.

Q2: Why does γ=1.4 for air?
A: 1.4 is the specific heat ratio for diatomic gases like air at standard conditions (γ = cₚ/cᵥ).

Q3: What happens if M₁ < 1?
A: The formula doesn't apply - shock waves only occur when M₁ ≥ 1 (supersonic flow).

Q4: Can this be used for other gases?
A: Yes, just use the appropriate γ value (e.g., 1.3 for CO₂, 1.67 for monatomic gases).

Q5: What other properties change across a shock?
A: Besides pressure, density, temperature, and Mach number also change dramatically.