Gas-surface interaction effect on round leading edge aerothermodynamics

Abstract

Effects of incomplete surface accommodation in rarefied gas flow have been studied by using the Direct Simulation Monte Carlo (DSMC) method in conjunction with the Cercignani-Lampis-Lord gas surface interaction model. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between full and partial surface accommodation for hypersonic flow past round leading edges at zero incidence. The aerodynamic performance of round leading edges is assessed by using the heat transfer rate, the total drag and the shock wave standoff distance. Twenty-five combinations of nose radius, normal and tangential accommodation coefficients were used in the simulation. For the flow conditions considered, the analysis showed that stagnation point heating, total drag and shock standoff distance are sensitive to changes on either the normal or tangential accommodation coefficient. The results substantiate that it becomes imperative to take surface accommodation into account in order to make accurate predictions of the aerodynamic forces on, and heat transfer rates to, bodies in rarefied hypersonic flow.

Pulsed Supersonic Beams from High Pressure Source: Simulation Results and Experimental Measurements

“…Not much is known for our nozzle surface (polished stainless steel or more recently polished ruby). We chose a perpendicular accommodation coefficient of 0.4 and a tangential accommodation coefficient of 0.4 [26][27][28][29] in the simulations to simulate helium. These coefficients determine the boundary layer thickness in the flow (between the flowing gas and the stationary nozzle surface).…”

Physical and computational aspects of shock waves over power-law leading edges

“…Nonetheless, smaller shock detachment distance is associated with a higher heat load to the nose of the body. The heat transfer coefficient C h ͑=2q w / ϱ V ϱ 3 ͒ at the stagnation point for power-law leading edges with n of 1 / 2 and 4 / 5 is 1.5 and 3.4 times larger than the heat transfer coefficient for the circular cylinder 42 at the same conditions.…”

“…In what follows, the reference circular cylinder 42 provides a much larger shock thickness, ␦ / ϱ of 3.350 at the same flow conditions. Compared to power-law leading edges, this value is about 2.1 and 6.4 times larger than the cases corresponding to power-law exponents of 1 / 2 and 4 / 5, respectively.…”

Effects of Gas-surface Interaction Models on Spacecraft Aerodynamics

“…Generally the interaction model has some (14) Here E w -energy of reflected molecules. If σ E ≠ 0, expression for the velocity of the reflected molecule looks like…”

“…For no significant additional cost, the CLL model gave more realistic scattering distributions [11]. CLL model is widely recognized examples of its application are presented in multiple works [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”