sci.reentry-heating-Fay-Riddell Calculator
Calculates heat flux during atmospheric re-entry using Fay-Riddell stagnation heating: q_s = 0.763 Pr^(−0.6) (ρ_w µ_w)^0.1 (ρ_e µ_e)^0.4 √(dU_e/ds) × (h_0 − h_w). Apollo capsule peak heat flux: 45 MW/m² — ablative heat shields prevent this reaching the vehicle through pyrolysis and mass loss.
Inputs
- V Ms
- Speed in a specified direction (m/s). Required for momentum, kinetic energy, and wave calculations.
- Rho Kgm3
- Mass per unit volume (kg/m³). Water: 1,000. Air: 1.225. Steel: 7,850. Affects buoyancy, flow, and structural loads.
- R Nose M
- Distance from centre to edge of a circle. Radius = diameter / 2.
- T Wall K
- Thermal state of the substance. Check whether the formula needs Celsius, Fahrenheit, or Kelvin (K = °C + 273.15).
Results
- stagnation point heat flux q
- The value at the specified point or condition.
- adiabatic wall temperature T_aw (K)
- The value at the specified point or condition.
- stagnation enthalpy equivalent (kJ/kg)
- The value at the specified point or condition.
- q
- Reference formula or conversion factor shown for context.
- TPS material context
- The value at the specified point or condition.
- trajectory context
- Sample size or count used in the calculation.
riddell atmospheric heat adiabatic stagnation