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ISSN Онлайн: 2642-0554

LES OF SEPARATED FLOWS AT MODERATE REYNOLDS NUMBERS APPROPRIATE FOR TURBINE BLADES AND UNMANNED AERO VEHICLES

F. Cadiuex
Department of Aerospace and Mechanical Engineering University of Southern California Los Angeles, California 90089-1191

G. Castiglioni
Department of Aerospace and Mechanical Engineering University of Southern California Los Angeles, California 90089-1191

J. Andrzej Domaradzki
University of Southern California, Department of Aerospace and Mechanical Engineering, Los Angeles, CA 90089-1191, U.S.A.

T. Sayadi
Center for Turbulence Research Stanford University Stanford, California, 94305

Sanjeeb T. Bose
Department of Mechanical Engineering Stanford University Stanford, California 94305, USA

Muzio Grilli
Lehrstuhl fur Aerodynamik und Stromungsmechanik Technische Universitat Munchen Boltzmannstr 15, D-85748 Garching, Germany

Stefan Hickel
Institute of Aerodynamics and Fluid Mechanics Technische Universitat Munchen Boltzmannstr. 15, 85748 Garching bei Munchen, Germany; Chair of Computational Aerodynamics Faculty of Aerospace Engineering, TU Delft Kluyverweg 1, 2629 HS Delft, Netherlands

Аннотация

Flows over airfoils and blades in rotating machinery, for unmanned and micro-aerial vehicles, wind turbines, and propellers consist of a laminar boundary layer near the leading edge that is often followed by a laminar separation bubble and transition to turbulence further downstream. Typical RANS turbulence models are inadequate for such flows. Direct numerical simulation (DNS) is the most reliable but is also the most computationally expensive alternative. This work assesses the capability of LES to significantly reduce the resolution requirements for such flows and still provide results of DNS quality. Two flows are considered. A flow over a flat plate with suitable velocity boundary conditions away from the plate to produce a separation bubble and a 2-D flow on a NACA-0012 airfoil. By employing several different codes we conclude that accurate LES are possible using O(1%) of the DNS resolution and that the numerical dissipation plays a significant role in LES of such flows.