Topical Problems of Fluid Mechanics


Institute of Thermomechanics AS CR, v.v.i.	CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics	MIO Université du Sud Toulon Var - AMU - CNRS - IRD	Czech Pilot centre ERCOFTAC

Calculation of Nonuniform Fluid Flows in a Gravity Field
Dimitrieva N., F.
Abstract:
Based on the open source software 2D numerical simulations of incompressible stratified fluids flows have been performed. They are characterized by a wide range of values of internal scales that are not found in a homogeneous liquid. Mathematical model is based on the set of differential equations of inhomogeneous multicomponent fluid mechanics. The method allows analyzing in a single formulation the dynamics and fine structure of flow patterns past obstacles in a wide range of flow parameters. The calculations were performed using parallel computational facilities of the web-laboratory UniHUB. The same system of equations and a general numerical algorithm were used for the whole range of the parameters under consideration. The calculation results are in a qualitative agreement with the data from laboratory experiments. Transient flow patterns past obstacles are analyzed, and physical mechanisms are determined, which are responsible for formation of vortices in regions with high density gradients near the edges of an obstacle. For all the velocities of the body motion, the flow field is characterized by a complicated internal structure. In the flow pattern around motionless body dissipative gravity waves are manifested at the edges of the strip. Around the slowly moving body a group of attached waves is formed in opposite phases at the edges of the wedge. Then, the main flow components become vortices, which are formed around the edge of the wedge and manifested downstream in the wake. With further increase in velocity of the body motion, the flow pattern becomes more non-stationary.
Keywords:
stratification, wedge, numerical simulation

Fulltext: PDF DOI: https://doi.org/10.14311/TPFM.2020.007

In Proceedings Topical Problems of Fluid Mechanics 2020, Prague, 2020 Edited by David Šimurda and Tomáš Bodnár, pp. 48-55 ISBN 978-80-87012-74-1 (Print) ISSN 2336-5781 (Print)