Correlation of HIFiRE-5a Flight Data with Computed Pressure and Heat Transfer (original) (raw)

Flight pressure and heat flux data have been compared to angle-of-attack-and yaw-dependent computational-fluid-dynamics results for pressure distribution as well as laminar and turbulent heat-transfer results at three time points in the ascent trajectory. Computed pressures, normalized by freestream pressure, were interpolated to the flight Mach numbers at each time point throughout the ascent and descent trajectories, and angle of attack and yaw were estimated from measured pressure by determining the combination minimizing the difference between the measured and computed pressures. The resulting vehicle attitude was compared to the vehicle attitude derived from inertial measurement unit results from the flight. The two methods showed excellent agreement for the entirety of the ascent and reentry portions of the trajectory. A similar normalization of the laminar and turbulent computational-fluid-dynamics heat transfer results into Stanton number distributions was compared to flight heat transfer measurements, and transition times at a given location were inferred. Computational heat conduction analysis verified assumptions in the calculation of heat flux from temperature. Nomenclature c p = specific heat capacity, constant pressure, J∕…kg ⋅ k† M = Mach number p = pressure, Pa _ q = heat flux, W∕m 2 Re = Reynolds number St = Stanton number T = temperature, K t = time, s u = velocity, m∕s x = streamwise distance, m α = angle of attack, deg β = yaw, deg ρ = density, kg∕m 3 ϕ = angular location on vehicle surface, deg Subscripts CFD = derived from computational solution CL = centerline e = boundary-layer edge conditions F = derived from flight measurement FFT = fast Fourier transform IMU = recorded by the inertial measurement unit LE = leading edge RMS = derived from root-mean-squared error minimization between computational fluid dynamics and flight tr = at transition onset w = wall conditions 0 = stagnation conditions ∞ = freestream conditions