Experimental and numerical investigations of transition laminar/turbulent on a capsule model in a hypersonic Ludwieg tube

本文将通过实验和数值模拟相结合的方法研究有入射的钝化r-大气层迎风侧三维边界层的转换层流/湍流。将彻底描述相关边界层不稳定性和非模式扭曲的发展。数值模拟基于二维特征值方法和求解抛物化稳定性方程的推广。它们还将考虑非模式扭曲的最优增长。数值结果将利用时间分辨压力测量、热传递测量和热丝测量的实验数据进行验证。此外，还将使用不同的探头形状和传感器系统地测量试验段中的自由流干扰。将在胶囊上放置定义明确的粗糙度元素，并记录它们对过渡过程的影响。这包括单一粗糙度元素和分布粗糙度。该项目为成功地将过渡分析外推到长期飞行条件奠定了基础。

Transition laminar/turbulent of the three dimensional boundary layer on the windward side of blunt r-entry capsules with incidence will be investigated experimentally and numerically. The development of the relevant boundary layer instabilities and non-modal distortions will be thoroughly characterized. The numerical simulations are based on a two-dimensional eigenvalue method and extensions to solve the parabolized stability equations. They will also take into account optimal growth of non-modal distortions. The numerical results will be validated by using experimental data from time-resolved pressure measurements, heat transfer measurements and hot-wire measurements inside the bow shock of the capsule. Furthermore, freestream disturbances in the test section will be systematically measured by using different probe shapes and sensors. Well-defined roughness elements will be positioned on the capsule and their effect on the transition process will be documented. This includes single roughness elements and distributed roughness. The project prepares the ground for successful extrapolation of transition analysis to flight conditions in the long term.