An LES study of the wake flow dynamics and heat transfer characteristics of two side-by-side finite wall-mounted square cylinders

This paper studies the wake flow dynamics and heat transfer characteristics of two side-by-side finite wall -mounted square cylinders through large-eddy simulations at Reynolds and Prandtl numbers of Re = 1.2 x 104 and Pr = 0.7. The influence of normalized center-to-center distances between cylinders (S/d, where d is the side of the cylindersMODIFIER LETTER PRIME cross-section) is investigated for S/d = 2-5, while both cylinders pose an identical aspect ratio of AR = 7. First, the numerical approach is validated against the published experimental data. Then the instan-taneous and time-mean wake flow structures, as well as the global quantities, turbulence statistics and heat transfer are studied. It is found that the biased/flip-flop flow at S/d = 2 turns into anti-phase coupled vortex shedding flow at S/d >= 3. This flow regime transition induces a relatively sharp change in drag coefficient and vortex shedding frequency, minimum values at S/d = 2 and maximum values at S/d = 3. The Nusselt number mildly changes at S/d >= 3. The turbulent deflected gap flow at S/d = 2 results in inequality of drag forces on and heat transfer from two cylinders. That is, the drag coefficient and Nusselt number are larger for the cylinder towards which the gap-flow is deflected. It is also shown that swinging the deflected gap flow at S/d = 2 is a more intense source of turbulence than the vortex shedding from lateral faces, albeit the Reynolds stress is magnified with increasing S/d. The flow interference is steadily reduced with S/d, almost faded at S/d = 5.

Automated summary

This paper investigates the wake flow dynamics and heat transfer characteristics of two side-by-side finite wall-mounted square cylinders through large-eddy simulations. It found that the flow regime transitions and induces changes in drag coefficient, vortex shedding frequency, and Nusselt number. The study also reveals the influence of flow interference and the intensity of turbulence generated by the deflected gap flow.