Influence of Turbulence Intensity and Turbulence Length Scale on the Drag, Lift and Heat Transfer of A Circular Cylinder |
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Authors: | IV Morenko and VL Fedyaev |
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Institution: | Institute of Mechanics and Engineering, Kazan Science Center, Russian Academy of Sciences (IME KazSC RAS), Kazan, Russian Federation and Institute of Mechanics and Engineering, Kazan Science Center, Russian Academy of Sciences (IME KazSC RAS), Kazan, Russian Federation;Kazan National Research Technical University named after A.N. Tupolev - KAI (KNRTU-KAI), Kazan, Russian Federation 2/31 Lobachevsky st. Kazan, Republic of Tatarstan, Russian Federation 420111 |
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Abstract: | Influence of the turbulence intensity and turbulence length scale on the hydrodynamic characteristics and heat transfer of a circular cylinder, streamlined by a viscous fluid flow, is numerically studied. We take the Reynolds number of the oncoming flow equal to 4×104, the turbulence intensity Tuf and the dimensionless turbulence length scale Lf varying from 1.0% to 40% and from 0.25 to 4.0, respectively. We confirmed that the increase of Tuf leads to the suppression of the periodic vortex shedding from the cylinder surface, and as a result the stationary mode of streamlining is formed. Consequently, with the increasing turbulence intensity directly in front of the cylinder Tu*, the amplitude of the lift coefficient decreases monotonically. Nevertheless, the time-averaged drag coefficient of the streamlined cylinder decreases at Tu*<6.0%, and increases at Tu*>9.0%. The dependence of the average Nusselt number on Tu* is near-linear, and with the increasing turbulence intensity, the Nusselt number rises. However, the change of the average Nusselt number depending on Lf is non-monotonic and at Lf=1.0, the value reaches its maximum. |
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Keywords: | hydrodynamics turbulence heat transfer of a circular cylinder |
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