Low-Speed DSMC Simulations of Hotwire Anemometers at High-Altitude Conditions

Numerical simulations of hotwire anemometers in low-speed, high-altitude conditions have been carried out using the direct simulation Monte Carlo (DSMC) method. Hotwire instruments are commonly used for in-situ turbulence measurements because their ability to obtain high spatial and temporal resolution data. Fast time responses achieved by wires having small diameters (1–5 ?m). currently being make (20–40 km). At these altitudes, hotwires experience Knudsen number values that lie transition-regime between slip-flow free-molecular flow. This article expands current knowledge investigating behavior transition-regime. Challenges involved with simulating at low Reynolds discussed. The DSMC method simulate from regimes is demonstrated. Dependence heat transfer on surface accommodation coefficient explored Simulation results Nusselt dependence show good agreement experimental Magnitude discrepancies attributed differences conditions, while trend finite domain size.