The influence of surface roughness as well as protrusion geometry laid over the inner wall of the horizontal channel, on mean velocity and turbulent quantities along with thermal quantities of the swirling steam-water flow are determined experimentally. These were compared with the measurements for those obtained for smooth inner surface of the channel. The test facility has comprised of a Perspex pipe having inner diameter of 15 cm and length 30 cm. It contains three sections; one has smooth inner surface, second has rough inner surface with mild sand blasting and the third has square circular protruded collars along with mild treatment with the sand blasting. Mean velocity profile within the region close to the vicinity of the surface roughness has been lower than the values of the mean velocity profile in case of smooth inner surface of the pipe. And mean velocity values with protruded collar along with roughened surface are even lower than those in case of inner rough surface. However, the mean velocity values at distance away from the rough surface match among the three cases. Similar profiles representative of the three surfaces are obtained in case of velocity deficit. Whereas different turbulent characteristics are observed among smooth, rough, and protruded surfaces. Significant influences on the normal and Reynolds stresses occur over the whole of the layer due to the rough and protruded surfaces than those of the stresses generated in case of smooth surface. Although velocity spectra exhibit differences between the three surfaces, the mean energy dissipation rate does not appear to be significantly affected by the roughness and protruded surface. Nusselt number with passage of time following initiation of steam into the pipe, drops to an equilibrium value after passage of about 50–70 s. And the heat transfer characterized by normalized Stanton number ratio of rough surface to smooth surface, increases with increase in size of the sand grain for all the three surfaces. The increase in Stanton number ratio representing the rough surfaces is higher than the values of ratio in case of smooth surface. However, the major outcome of this study has been owed to the vorticities shed through the roughness, which is comparable to the roughness scale, k and this was found substantial than the turbulence scale of the outer layer.

通过实验确定了表面粗糙度以及水平通道内壁上的突起几何形状对平均速度和湍流量以及涡流蒸汽-水流的热量的影响。将这些与通道光滑内表面的测量值进行比较。测试设备由内径为 15 厘米、长度为 30 厘米的有机玻璃管组成。它包含三个部分；一个内表面光滑，第二个内表面粗糙，经过轻度喷砂处理，第三个带有方形圆形突出环，并经过喷砂处理。靠近表面粗糙度附近区域内的平均速度分布低于管道内表面光滑情况下的平均速度分布值。并且带有突出轴环和粗糙表面的平均速度值甚至低于内部粗糙表面的平均速度值。然而，远离粗糙表面的平均速度值在三种情况下是匹配的。在速度不足的情况下，可以获得代表三个表面的类似轮廓。而在光滑、粗糙和突出的表面之间观察到不同的湍流特性。由于粗糙和突出的表面，对整个层的法向和雷诺应力影响显着，而不是在光滑表面情况下产生的应力。尽管速度谱在三个表面之间表现出差异，但平均能量耗散率似乎不受粗糙度和突出表面的显着影响。在蒸汽开始进入管道后，努塞尔数随着时间的推移，在经过大约 50-70 秒后下降到一个平衡值。并且以粗糙表面与光滑表面的归一化斯坦顿数比为特征的传热随着所有三个表面的砂粒尺寸的增加而增加。代表粗糙表面的斯坦顿数比的增加高于光滑表面情况下的比值。然而，这项研究的主要结果归功于通过粗糙度脱落的涡度，这与粗糙度尺度相当，