| 초록 |
Yield stress fluid is widely used in real life, but the flow mechanism is not clearly elucidated. When performing the capillary rise experiment, the yield stress has an h-t curve with a bend point, unlike a simple fluid. To know this flow mechanism of yield stress fluid, we tried calculating the capillary force. As a first step, we measured the surface tension. The du nouy ring method, pendant drop, and Wilhelmy plate method were performed. Unlike simple fluids, those methods were difficult to measure the tension because of its low velocity flow and long time viscous effect. Currently, we perform a capillary bridge system which was made with two parallel plates. Images were obtained by changing the gap between the two plates. Finally, the surface tension is calculated by measuring the contact angle and analyzing the meniscus profile. |
