Accession Number:

AD0641202

Title:

MACHINE COMPUTATION OF AERODYNAMIC LOADS IN LINEAR AND NONLINEAR SITUATIONS,

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE FLUID DYNAMICS RESEARCH LAB

Personal Author(s):

Report Date:

1966-07-01

Pagination or Media Count:

32.0

Abstract:

The paper reviews recent successful efforts to determine the near field, i.e., to find the pressure distribution experienced by such surfaces. These involve a complete linearization of the governing differential equations and boundary conditions. With the object of escaping from the linear constraint -- often a very restrictive one -- recipes are given for higher-order calculations in two important situations. For inviscid, constant-density fluid flow, where the differential equation is linear, source and vortex methods have already been published whereby certain cases with nonlinear boundary conditions can be effectively analyzed. A new procedure is described which will permit the analysis of general three-dimensional wings, with circulation and a specified trailing-edge flow-off condition, by means of potential doublet sheets. It constructs the flow by computing transient fluid response from an undisturbed initial condition and is therefore specially adapted to unsteady-flow problems. The second case discussed involves certain second-order effects on loading in rectilinear supersonic flight, again allowing for unsteady effects of simple harmonic motion. It is shown how the linear solution for a source sheet can be modified to account for coupling with the steady flow due to thickness. Velocity potential sources are distributed over many small rectangular area elements and their loading contributions superimposed in the manner of aerodynamic influence coefficients. Author

Subject Categories:

  • Fluid Mechanics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE