Enhancement of heat transfer is very important in many engineering applications. The present study explores one of such possibilities by increasing the surface area of a plane wall. The effect of wavy wall on thermal and flow characteristics of a turbulent wall jet is studied in detail. The amplitude of the wavy surface is varied between 0.1 and 0.7 with an interval of 0.1. The Reynolds number is set to 15,000. The Reynolds averaged Navier Stokes equations are solved using the finite volume approach. The semi-implicit pressure linked equation algorithm is used to couple the pressure and velocity. A new scale, other than the traditional outer scaling, is defined for carrying out the self-similar behavior of the flow. Unlike the plane wall case, the self-similar characteristic is obtained at the respective crests and the troughs. However, it is also noticed that the two characteristics differ significantly with each other. Even, these characteristics are found to differ with each other for different amplitudes. The minimum pressure near the nozzle decreases as the amplitude increases and it is noted to be equal to −0.541 for the highest amplitude, i.e. A = 0.7. It is observed that the strength of convection near the exit of the jet is very high, and it decreases in the downstream direction. This increase in convection augments heat transfer by almost 10% as compared to the plane wall case. Based on the results, a quartic curve is fit for the average Nusselt number with a 99.75% goodness of fit. It is expected that the present study opens a new line in designing a proper cooling system.

中文翻译：

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使用湍流壁射流增强传热

增强传热在许多工程应用中非常重要。本研究通过增加平面墙的表面积来探索其中一种可能性。详细研究了波浪壁对湍流壁射流热特性和流动特性的影响。波浪表面的振幅在0.1和0.7之间变化，间隔为0.1。雷诺数设置为 15,000。雷诺平均 Navier Stokes 方程使用有限体积方法求解。压力和速度耦合采用半隐式压力关联方程算法。定义了一个新的尺度，而不是传统的外部尺度，用于执行流的自相似行为。与平面壁的情况不同，在各自的波峰和波谷处获得自相似特性。然而，还注意到这两个特征彼此显着不同。甚至，发现这些特性对于不同的幅度彼此不同。喷嘴附近的最小压力随着振幅的增加而降低，并且注意到对于最高振幅等于 -0.541，即 A = 0.7。观察到射流出口附近的对流强度非常高，并且在下游方向上减弱。与平面壁情况相比，这种对流的增加使热传递增加了近 10%。根据结果​​，四次曲线拟合平均 Nusselt 数，拟合优度为 99.75%。预计本研究为设计合适的冷却系统开辟了一条新途径。发现这些特性对于不同的幅度彼此不同。喷嘴附近的最小压力随着振幅的增加而降低，并且注意到对于最高振幅等于 -0.541，即 A = 0.7。观察到射流出口附近的对流强度非常高，并且在下游方向上减弱。与平面壁情况相比，这种对流的增加使热传递增加了近 10%。根据结果​​，四次曲线拟合平均 Nusselt 数，拟合优度为 99.75%。预计本研究为设计合适的冷却系统开辟了一条新途径。发现这些特性对于不同的幅度彼此不同。喷嘴附近的最小压力随着振幅的增加而降低，并且注意到对于最高振幅等于 -0.541，即 A = 0.7。观察到射流出口附近的对流强度非常高，并且在下游方向上减弱。与平面壁情况相比，这种对流的增加使热传递增加了近 10%。根据结果​​，四次曲线拟合平均 Nusselt 数，拟合优度为 99.75%。预计本研究为设计合适的冷却系统开辟了一条新途径。541 为最高振幅，即 A = 0.7。观察到射流出口附近的对流强度非常高，并且在下游方向上减弱。与平面壁情况相比，这种对流的增加使热传递增加了近 10%。根据结果​​，四次曲线拟合平均 Nusselt 数，拟合优度为 99.75%。预计本研究为设计合适的冷却系统开辟了一条新途径。541 为最高振幅，即 A = 0.7。观察到射流出口附近的对流强度非常高，并且在下游方向上减弱。与平面壁情况相比，这种对流的增加使热传递增加了近 10%。根据结果​​，四次曲线拟合平均 Nusselt 数，拟合优度为 99.75%。预计本研究为设计合适的冷却系统开辟了一条新途径。