Similar Solutions of the Three Dimensional Boundary Layer with Constant Cross Flow


Book Description

Governing equations are formulated for laminar compressible similar boundary layers with heat transfer, adverse pressure gradient, and constant cross flow. These equations are expressed in finite difference form and solved numerically. Solutions are found for attached and separated flows in adverse pressure gradients for nine combinations of cross flow and heat transfer. The purpose of these solutions is to provide understanding of how cross flow alters the two-dimensional similar results. Solutions are presented in the form of temperature profiles, main flow and cross flow velocity profiles, and global quantities; wall velocity and temperature gradients, displacement thickness, momentum thicknesses, and form factor.




The Singular Nature of Three-dimensional Perturbations of Boundary Layers and the Small Cross Flow Theory


Book Description

Three-dimensional perturbations on two-dimensional boundary layer flows are considered. First initially induced perturbations are studied and a general solution obtained. Second a specific externally induced perturbation is discussed. In both the streamwise velocity perturbation becomes infinite but the cross flow decays as downstream infinity is approached. This implies that the small cross flow approximation is a singular perturbation. The basis for this lies in the fact that the nature of the equations is changed by the approximation, viz., the zone of dependence property is lost.







Small Cross-flows in Three-dimensional Laminar Boundary Layers with Suction Or Injection


Book Description

Three-dimensional laminar boundary layers with suction or injection are examined by using an approximate method based on a small cross-flow assumption. The basic equations are derived in detail and the computational method is developed. The method is tested against exact solutions and is found to be reasonably accurate. Two examples with the same external condition, but with different surface conditions, are analyzed. In one case the distribution of the normal velocity at the surface satisfies the similarity requirement and in the other case the normal velocity is constant over the complete surface. Although the results of these two cases are different in detail, the general trend of both shows that the three-dimensional behaviour of the boundary layer diminishes with suction and amplifies with injection. (Author).




Boundary-layer Similar Solutions and Correlation Equations for Laminar Heat-transfer Distribution in Equilibrium Air at Velocities Up to 41,100 Feet Per Second


Book Description

Correlations of the transport property estimates of NASA TR R-50 are employed to determine locally similar solutions of the laminar boundary-layer equations for air in chemical equilibrium. Exact solutions for flat-plate flow, axisymmetric stagnation flow, and stagnation flow for yawed infinite cylinder are obtained, and a correlation formula for the heat-transfer distribution function for arbitrary favorable pressure gradient is determined. Extension to three-dimensional flows with small cross flow is briefly described.













Separated Flow Studies


Book Description

This report reviews the progress over the last decade on separated flows conducted at these laboratories. Experimental investigations conducted in the hypersonic wind tunnels is discussed. Advancements are summarized in the theoretical area which cover the development of interacting boundary layers to the numerical computation of the complete Navier-Stokes equations.