بررسی اثرات نوسانی ناشی از جریان و بهبود انتقال حرارت حول استوانه ثابت فوق‌آبگریز

Vortex shedding is an oscillatory phenomenon that occurs when a fluid flows past a bluff body, such as a cylinder, at specific velocities. This phenomenon can lead to vortex-induced vibrations, resulting in structural fatigue. In the present study, numerical simulations of transient flow and convective heat transfer around a superhydrophobic cylinder are conducted to enhance the heat transfer coefficient and reduce both drag and lift coefficients. The governing equations are solved using the finite volume method, employing the SIMPLE algorithm. For validation purposes, the Nusselt number results for a cylinder with a no-slip boundary condition are initially compared with previous studies, demonstrating satisfactory agreement. Subsequently, the Navier boundary condition is applied to the hydrophobic cylinder using a user-defined function (UDF), and the results are validated against available numerical data from the literature. The simulations are performed for a Prandtl number of 0.7 and various Reynolds numbers and slip lengths, examining the influence of surface slip on the drag and lift coefficients, the Strouhal number, and the heat transfer coefficient. The findings reveal that, for a Reynolds number of 100 and a slip length of 0.2, the Nusselt number increases by 21.3%, while the drag coefficient is reduced by 50.25%, effectively suppressing and controlling vortex shedding around the cylinder. Additionally, the oscillatory behavior of the Nusselt number is mitigated at this slip length. Furthermore, it is observed that, at various Reynolds numbers, an increase in slip length results in an increase in the Nusselt number and a reduction in force coefficients.