Two-dimensional unsteady inertial flows of a yield stress fluid around a cylinder were studied experimentally. Carbopol aqueous gels, well-known model yield stress fluids, are used. The influence of interface conditions on vortex shedding was studied in particular by modifying the roughness of the cylinder. When wall adherence was guaranteed, it was possible to observe alternate vortex shedding similar to the Von Karman street occurring in Newtonian fluids. In contrast, when the fluid was able to slip on the cylinder wall, a highly particular flow morphology was observed. The effects of the Reynolds and Oldroyd numbers and that of confinement on the critical Reynolds number for vortex shedding and on the Strouhal number were demonstrated. The experimental results were compared with the numerical predictions using a Herschel-Bulkley viscoplastic model.

实验研究了屈服应力流体绕圆柱体的二维非定常惯性流动。使用 Carbopol 水凝胶，众所周知的模型屈服应力流体。特别是通过修改圆柱体的粗糙度来研究界面条件对涡旋脱落的影响。当壁面粘附得到保证时，可以观察到类似于牛顿流体中发生的 Von Karman 街的交替涡流脱落。相比之下，当流体能够在气缸壁上滑动时，观察到非常特殊的流动形态。证明了雷诺数和奥德罗伊德数以及限制对涡旋脱落的临界雷诺数和斯特劳哈尔数的影响。