A review of impinging jets during rocket launching

During rocket launching, the engine exhaust impinges on the launch structures, such as the launch platform and the jet deflector, leading to a complex flowfield and generating strong noise. The engine exhaust impingement induces large aerothermodynamic and acoustic loads on the launch structures and the rocket, the overload of which is a potential risk to the rocket launch. Thus, it is important to predict and reduce the loads. Although the jet impingement during rocket launching has been studied extensively, the jet impingement during rocket launching is a complex phenomenon, where multiple mechanisms are coupled. In most researches, several mechanisms are studied separately or in a partially-coupled way. Still, there are a lot of issues on the jet impingement remaining to be solved, especially when quantitative relations are taken into account. In this article, several issues involved are reviewed, to present an overview on progresses and perspectives of the jet impingement research for rocket launching. It starts with a summary of the results accessed for normal and inclined jets impinging on flat plates, then the interactive mechanisms between impinging jets and the launch platform or the deflector system, together with relevant factors that affect the flowfield and noise. Additionally, discussions on the interaction of impinging jets with multiphase flows are also presented.