Compressible Viscous Flowfields and Airframe Forces Induced by Two-Dimensional Lift Jets in Ground Effect.

摘要

The interaction of the lift jets and the ground is an important consideration with regard to the design of VTOL aircraft. A key element of this ground effect problem is turbulent jet entrainment, which causes otherwise static air to be set into motion and leads to aerodynamic loads on airframe surfaces. To gain a better understanding of this phenomenon, a theoretical analysis of two-dimensional (planar) compressible turbulent jet impingement flowfields has been undertaken. Lift jets emanating from flat and curved surfaces in close ground effect have been modeled using the compressible Reynolds equations in combination with a one-equation turbulence model. Distributions of the flow properties are computed as functions of the Reynolds, Prandtl, and Froude numbers and height of the jet exit plane above ground. (Author)