This article is devoted to studying the initial-boundary value problem for an ideal polytropic model of non-viscous and compressible gas. We focus our attention on the outflow problem when the flow velocity on the boundary is negative and give a rigorous proof of the asymptotic stability of both the degenerate boundary layer and its superposition with the 3-rarefaction wave under some smallness conditions. New weighted energy estimates are introduced, and the trace of the density and velocity on the boundary are handled by some subtle analysis. The decay properties of the boundary layer and the smooth rarefaction wave also play an important role.

中文翻译：

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无粘性导热理想气体流出问题的边界层渐近稳定性和稀薄波

本文致力于研究非粘性可压缩气体理想多方模型的初边值问题。当边界上的流速为负时，我们将注意力集中在流出问题上，并严格证明了简并边界层及其与 3-稀疏波在某些小条件下叠加的渐近稳定性。引入了新的加权能量估计，并通过一些微妙的分析处理边界上的密度和速度轨迹。边界层的衰减特性和平滑的稀疏波也起着重要作用。