Comprehensive study of forced convection over a heated elliptical cylinder with varying angle of incidences to uniform free stream
share
In this paper we carry out a numerical investigation of forced convection heat transfer from a heated elliptical cylinder in a uniform free stream with angle of inclination θ^∘. Numerical simulations were carried out for 10 ≤ Re ≤ 120, 0^∘≤θ≤ 180^∘, and Pr = 0.71. Results are reported for both steady and unsteady state regime in terms of streamlines, vorticity contours, isotherms, drag and lift coefficients, Strouhal number, and Nusselt number. In the process, we also propose a novel method of computing the Nusselt number by merely gathering flow information along the normal to the ellipse boundary. The critical Re at which which flow becomes unsteady, Re_c is reported for all the values of θ considered and found to be the same for θ and 180^∘ -θ for 0^∘≤θ≤ 90^∘. In the steady regime, the Re at which flow separation occurs progressively decreases as θ increases. The surface averaged Nusselt number (Nu_av) increases with Re, whereas the drag force experienced by the cylinder decreases with Re. The transient regime is characterized by periodic vortex shedding, which is quantified by the Strouhal number (St). Vortex shedding frequency increases with Re and decreases with θ for a given Re. Nu_av also exhibits a time-varying oscillatory behaviour with a time period which is half the time period of vortex shedding. The amplitude of oscillation of Nu_av increases with θ.
READ FULL TEXT
