An approximate method for computing inviscid vortex wake roll-up. Part II. Description of computer program vor2DT

An approximate method for computing inviscid vortex wake roll-up. Part II. Description of computer program vor2DT

Hoeijmakers, H.W.M.

National Aerospace Laboratory NLR

1985-11-15

In Part I if this report a method is described for approximately computing the shape of the steady vortex wake downstream of an aircraft configuration in steady flight through the unsteady analogy. In the analogy the steady fully three-dimensional problem is reduced to a two-dimensional time-dependent problem, corresponding to the evolution of a two-dimensional vortex sheet in successive cross flow planes. The geometry of the vortex wake in any cross-flow plane consists of independent segments. Each segment is built up ut of a continuous vortex sheet and up to two concentrated vortices which model tightly rolled-up vortex cores. Each of the vortices is connected to one of the edges of the continuous vortex sheet. Both single- and double-branched vortices can be accommodated. The method optionally accounts for symmetry and tunnel-wall influence, as well as for cross-flow plane components of the free stream. A second-order panel method is employed to compute the velocity induced by the vortex sheet and a modified Euler scheme is employed for the integration in time. By employing a curvature-dependent panel scheme the accuracy is enhanced and the formation of new rolling-up regions can be predicted quite realistically. In this part of the report the computer program developed, designated V0R2DT, is described in some detail .

http://resolver.tudelft.nl/uuid:4db02a34-1815-4eaf-86cf-27444ba04924

Nationaal Lucht- en Ruimtevaartlaboratorium

Campus only

NLR-TR 85149 U

Aerospace Engineering Reports

report

(c)1985 National Aerospace Laboratory NLR