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Turbulent jet in crossflow analysis with LES approach

Mojtaba Tahani (Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran)
Mohammad Hojaji (Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran)
Seyed Vahid Mahmoodi Jezeh (Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran)

Aircraft Engineering and Aerospace Technology

ISSN: 0002-2667

Article publication date: 3 October 2016

291

Abstract

Purpose

This study aims to investigate effects of sonic jet injection into supersonic cross-flow (JISC) numerically in different dynamic pressure ratio values and free stream Mach numbers.

Design/methodology/approach

Large Eddy simulation (LES) with dynamic Smagorinsky model is used as the turbulence approach. The numerical results are compared with the experimental data, and the comparison shows acceptable validation.

Findings

According to the results, the dynamic pressure ratio has critical effects on the zone related to barrel shock. Despite free stream Mach number, increasing dynamic pressure ratio leads to expansion of barrel shock zone. Consequently, expanded barrel shock zone would bring about more obstruction effect. In addition, the height of counter-rotating vortex pair increases, and the high-pressure area before jet and low-pressure area after jet will rise. The results show that the position of barrel shock is deviated by increasing free stream Mach number, and the Bow shock zone becomes stronger and close to barrel shock. Moreover, high pressure zone, which is located before the jet, decreases by high free stream Mach number.

Practical implications

In this study, LES with a dynamic Smagorinsky model is used as the turbulence approach. Effects of sonic JISC are investigated numerically in different dynamic pressure ratio values and free stream Mach numbers.

Originality/value

As summary, the following are the contribution of this paper in the field of JISC subjects: several case studies of jet condition have been performed. In all the cases, the flow at the nozzle exit is sonic, and the free stream static pressure is constant. To generate proper grid, a cut cell method is used for domain modelling. Boundary condition effect on the wall pressure distribution around the jet and velocity profiles, especially S shape profiles, is investigated. The results show that the relation between representing the location of Mach disk centre and at transonic regime is a function of second-order polynomial, whereas at supersonic regime, the relationship is modelled as a first-order polynomial. In addition, the numerical results are compared with the experimental data demonstrating acceptable validation.

Keywords

Citation

Tahani, M., Hojaji, M. and Mahmoodi Jezeh, S.V. (2016), "Turbulent jet in crossflow analysis with LES approach", Aircraft Engineering and Aerospace Technology, Vol. 88 No. 6, pp. 717-728. https://doi.org/10.1108/AEAT-10-2014-0167

Publisher

:

Emerald Group Publishing Limited

Copyright © 2016, Emerald Group Publishing Limited

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