Abstract
The applicability of the solution of the unsteady Reynolds-averaged Navier–Stokes equations (URANS) for the numerical simulation of the periodic quasi-switching regime of vortex generation and heat transfer in a deep conical dimple with a slope angle of 10∘ on the wall of a narrow channel is substantiated. To calculate the turbulent regime, the model of shear stress transfer by Menter 2003, modified taking into account the influence of the curvature of streamlines within the framework of the Rodi-Leshziner-Isaev approach, is used. At Reynolds number Re=104, the oscillation period of the transverse Rz and longitudinal forces Rx, as well as the total heat transfer Numm to the control section of the heated channel wall with a dimple, is set equal to 60, which corresponds to the Strouhal number St=0.0167. Computer visualization of swirling jet-vortex flows demonstrates focus-type sources on the side faces of the dimple. In the self-oscillating mode, a two-cell vortex system is formed with different intensities at the oscillation period Rz. Periodic changes in friction, Nusselt numbers and temperature are recorded in the longitudinal and transverse median sections of the dimple and reflect the oscillations of the vortex structure from left to right and from right to left. The formation of a fan jet is shown, which oscillates relative to the plane of longitudinal symmetry, causing a redistribution of power and thermal loads.
Highlights
The problem of modeling self-oscillating modes of unsteady separated flow around objects with periodic vortex formation is one of the actual problems of hydromechanics.Self-oscillations of vortex structures are accompanied by periodic changes in local characteristics, as well as local and integral force loads on objects
Positive experience has been accumulated in the numerical prediction of the characteristics of turbulent flow based on the solution of unsteady Reynolds-averaged Navier–Stokes equations (URANS) [1,2,3,4,5,6], modeling by Large Eddy Simulation (LES) [7,8,9,10] and Direct Numerical Simulation (DNS) [11]
It is important to note that using URANS it is possible to identify the process of the formation of unsteady spatial jet-vortex structures and determine the effect of the height of the protrusion on it
Summary
Sergey Isaev 1,2 , Dmitry Nikushchenko 1 , Alexandr Sudakov 2 , Nikita Tryaskin 1, * , Ann Egorova 1 , Leonid Iunakov 3 , Alexandr Usachov 4 and Valery Kharchenko 2. Numerical Simulation of a Periodic Quasi-Switching Mode of Flow around a Conical Dimple with a Slope Angle of 10 Degrees on the Wall of a Narrow Channel Using
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