Three-dimensional instability mechanism in a four-vortex ...

Technical Note
(For internal use by AWIATOR partners and Commission only)
Three-dimensional instability mechanism
in a four-vortex system; Benchmark
computations.
Prepared by: H.L.C. Moet (CERFACS)
Work Package: WP1
Task: 1.1.1
Document No.: AW-CERFACS-111-001
Version: 1 (Draft)
Issued by: CERFACS
Date: July 17, 2003
Approved by:
Task Manager:
Issueing organisation: CERFACSThree-dimensional instability mechanism
in a four-vortex system; Benchmark
computations.
Henri Moet
CERFACS, Centre Europ¶een de Recherche et de Formation Avan»c¶ee en Calcul Scientiflque,
42, Av. G. Coriolis, 31057 Toulouse Cedex, France
Abstract. To compare difierent numerical methods, a "benchmark" computation has been
deflned within Subtask 1.1.1 "Design and Manufacture". The benchmark con-
sists in simulating the unstable behaviour of a four-vortex system composed of two counter-
rotating vortex pairs. An energy diagnostic is applied to analyse the evolution of the kinetic
energy in the vortex o w governed by the instability mechanism with the purpose of esti-
mating the artiflcial/numerical viscosity efiects. It is essential to demonstrate that numerical
efiects are within acceptable limits which allows the use of the numerical methods for pre-
dicting and selecting the desired vortex o w conflgurations.
July 17, 2003Table of Contents
1 Introduction............................................. 6
2 The numerical model and initial condition ................... 7
2.1 The numerical code NTMIX3D ........ ...