Analysis of low Reynolds number flow around a heated circular cylinder

Abstract

The objective of this study is to investigate the forced convection from and the flow around a heated cylinder. Experimental and computational results are presented for laminar flow around a heated circular cylinder with a diameter of 10 mm. The experiments were carried out using Particle Image Velocimetry (PIV) in a wind tunnel, and numerical simulations using an in-house code and a commercial software package, FLUENT. This paper presents comparisons for vorticity and temperature contours in the wake of the cylinder. Experimental and computational results are compared with those available in the literature for heated and unheated cylinders. An equation is suggested for a temperature-dependent coefficient defining a reference temperature to be used in place of the constant used in other studies. An attempt is also made to correct differences between average cylinder surface temperature and measured interior temperature of the cylinder.

On the effective temperature and Reynolds number concept for a heated circular cylinder: commentary of the article by Baranyi et al.

“…[1] was focused on fluid dynamics and heat transfer of a heated circular cylinder in air cross flow. The measurements covered the following ranges of the Reynolds number and the temperature ratio: Re = U ∞ D/ν ∞ = 195, 227, 388, and T*=T w /T ∞ =1.00, 1.26, 1.59, 1.93, 2.27, respectively, where U ∞ is the free-stream velocity, D is the cylinder diameter, ν ∞ is the kinematic viscosity related to the free-stream temperature T ∞ , and T w is the cylinder wall temperature.…”

“…Ref. [1] raises many questions related to fluid dynamics and heat transfer, such as two-dimensionality vs. three-dimensionality of wake flow, laminar vs. transitional wake regimes, forced vs. mixed convection, adjustment of facilities, application of methods, calibration of instruments, and so on. To make this commentary as brief as possible, it is focused on the highly challenging point of interpretation, namely, on the effective temperature concept.…”

“…The reason for this commentary is to clarify this concept because it seems to be applied/interpreted in a confusing manner in Ref. [1].…”

“…1(a) shows the comparisons of experimental St-Re data from Refs. [1] and [11]. Moreover, the St-Re correlation of the isothermal case (T*=1.00) in the range of Re=49-180 by Williamson and Brown [4] are plotted as the reference in Fig.…”

“…It is a pity that no descriptions of the efforts taken to avoid the oblique vortex shedding were mentioned in Ref. [1]. Fig.…”