Low-Speed Aerodynamics

Abstract

Low-speed aerodynamics is important in the design and operation of aircraft flying at low Mach number, and ground and marine vehicles. This 2001 book offers a modern treatment of the subject, both the theory of inviscid, incompressible, and irrotational aerodynamics and the computational techniques now available to solve complex problems. A unique feature of the text is that the computational approach (from a single vortex element to a three-dimensional panel formulation) is interwoven throughout. Thus, the reader can learn about classical methods of the past, while also learning how to use numerical methods to solve real-world aerodynamic problems. This second edition has a new chapter on the laminar boundary layer (emphasis on the viscous-inviscid coupling), the latest versions of computational techniques, and additional coverage of interaction problems. It includes a systematic treatment of two-dimensional panel methods and a detailed presentation of computational techniques for three-dimensional and unsteady flows. With extensive illustrations and examples, this book will be useful for senior and beginning graduate-level courses, as well as a helpful reference tool for practising engineers.

Effects of Wake Shapes on High-Lift System Aerodynamic Predictions

“…For most wing-body configurations, aligning the wake with the streamwise direction produces adequate results. However, as was found in [7], even an analysis of a simple, single wing can produce an array of results depending on the type of wake chosen.…”

“…For example, solid-core models that limit the maximum induced velocities eliminate some of the numerical issues [7]. In this case, however, the size of the core can easily become a driving factor of the solution, especially in the presence of strong wake interactions.…”

“…For modern conceptual design, three-dimensional panel methods and lifting surface methods are employed to estimate the aerodynamic performance of high-lift devices [2,3,6]. Potential flow methods, such as these, can use vortex filaments to model the shear layer in the wake [7][8][9]. The strength of these wake filaments depends on the change in the circulation along the trailing edge of the wing.…”

Swimming in an inviscid fluid

“…In Figure 2, the deformable body is assumed to start from rest (zero momentum). The velocity potentials ϕ − are computed at each time step using a panel method (see [7]). A standard 4 th -order Runge-Kutta scheme is used to integrate (2) for both the oscillatory and undulatory case.…”

Wing Lift-Drag Ratio Optimization

“…Typically, the fuselage outer mold line is divided into numerous panels around the perimeter and multiple segments along the length [4]. Also, the surfaces of wing and tail are paneled individually, rather than simply modeling the camber line with the VLM method.…”