Discussion Of 'flow Intensity Parameter In Pier Scour Experiments' Gonzalo Simarro, Luis Teixeira, Antonio H. Cardoso

摘要

The discussers appreciate the authors' efforts in presenting the significance of flow intensity in relation to scour depth around bridge pier under clear-water conditions. Through dimensional analysis, the authors pointed out that if the viscous effect indeed plays a negligible role in the local scour phenomenon, as many investigators suggested, then the flow intensity should be defined as u/u_c instead of u/u_c. Herein, u_c=pseudocritical velocity defined in Eq. (20) in the paper and u_c=critical velocity defined in Eq. (8). The discussers are in agreement with the authors in their physical reasoning behind the dimensional analysis. However, comparing those two plots in Fig. 2 of the original paper, one can hardly conclude that the use of u/u_c improves the correlation. As a matter of fact, when ulu_c is employed, the data set with h/d_(50) ≈ 208 (marked with crosses) deviates significantly from the other two sets with h/d_(50) ≈ 13. In other words, this deviation is attributable to flow depth effect, which should be taken into account to improve the correlation in all series.