Flow separation characteristics on diamond wing for various leading-edge roughness

在以中等前缘后掠角和钝前缘为特征的机翼构型中，气流在中等迎角下在前缘区域分离，而随后的涡流形成仅在前缘的一部分上延伸。朝向顶点有附着流。流动分离拓扑结构特别取决于雷诺数和前缘的粗糙度，即，主要分离是与层流、过渡或湍流型边界层相关联还是与粗糙壁相关联的湍流分离相关联。此外，由于适度的前缘后掠角，部分发展的涡在相对较短的发展长度后已经破裂。除了实际的前缘涡（主涡）外，沿内翼部分沿着可能有进一步的涡状流动分离。与具有强的、完全发展的前缘涡的情况相比，与部分发展的前缘涡及其主要参数相关的精确分析证明了进一步详细研究的合理性。因此，本项目的目的是研究部分发展的前缘涡的演变和发展，以及相应的流动分离，作为边界层状态和前缘粗糙度的函数，使用一般的菱形机翼构型。必须进行补充的风洞试验和数值模拟。由此导出涡结构的特征和瞬态特性的判据。另一个目标是评估使用Navier-Stokes方法来解决这个问题的质量方面的结果，采用尺度自适应湍流模型和尺度分辨率技术。

At wing configurations featuring moderate leading-edge sweep and blunt leading-edges, the flow separates in the leading-edge area at moderate angles of attack while the subsequent vortex formation extends only over a portion of the leading-edge. Towards the apex there is attached flow. The flow separation topology depends in particular on the Reynolds number and the roughness of the leading edge, i.e. whether the primary separation is associated with a laminar, transition or turbulent type boundary layer or a turbulent separation linked to a rough wall. In addition, due to the moderate leading-edge sweep, the partially developed vortex already burst after a relatively short development length. Apart from the actual leading-edge vortex (main vortex) there may be a further vortex-like flow separation along the inner wing part. In contrast to the cases with strong, fully developed leading- edge vortices, a precise analysis associated with partially developed leading-edge vortices and their main parameters justify detailed further research. Consequently, the objective of this project is to investigate the evolution and development of partly developed leading-edge vortices and corresponding flow separation as a function of the boundary layer state and leading-edge roughness using a generic diamond wing configuration. Complementary wind tunnel tests and numerical simulations have to be performed. Thus, features of the vortex structures and criteria for the transient characteristics are to be derived. Another objective is to evaluate the use of Navier-Stokes methods to this problem in terms of the quality of results, employing scale adaptive turbulence modeling and scale resolution techniques.