A method of direct numerical simulation and a method of solving the boundary-layer equations were applied to parameters of a supersonic boundary layer for a flow past a flat plate (Mach number M = 2) for the case of a plate coated with a sublimation material. The sublimating material is naphthalene (C₁₀ H₈). Comparison of results from these two approaches — numerical simulation and solution of a boundary layer under the assumption on the local self-similarity — demonstrated a satisfactory agreement between them. Calculations demonstrated that a higher surface temperature produces a higher mass rate of evaporation. Meanwhile, the total heat flux to the solid wall decreases and the wall temperature is lower than for the case of zero sublimation. Since the molecular mass of naphthalene is by several times higher than the molecular mass of air and due to evaporation-induced wall cooling, we observe a higher density of the mixture of air with the sublimating substance vapor near the wall. This may facilitate a higher stability of the supersonic boundary layer and delays the flow transition to the turbulent state.

中文翻译：

---

表面材料升华时超声速流过平板的数值模拟

对于流经平板（马赫数M = 2）的超音速边界层的参数，将直接数值模拟方法和边界层方程组的求解方法应用于平板上涂有升华材料的情况。升华材料是萘（C ₁₀ H ₈）。比较这两种方法的结果-数值模拟和在假设局部自相似的情况下边界层的求解-证明了它们之间的令人满意的一致性。计算表明，较高的表面温度产生较高的蒸发质量速率。同时，与零升华情况相比，流向实心壁的总热通量降低，壁温降低。由于萘的分子量比空气的分子量高出几倍，并且由于蒸发引起的壁冷却，我们观察到壁附近的空气与升华物质蒸气的混合物的密度更高。这可以促进超音速边界层的更高的稳定性并且延迟流向湍流状态的过渡。