Experimental Investigation of Gravity Current Frontal Velocity on Rough Beds

Abstract

The frontal of gravity current is most important section of theseflowtypes. The advance force in front is pressure gradient due to densitydifferences betweenfront flow andambient fluid. In order to find the roughness effects as a resistor on frontalvelocity, a series experiment of saline gravity currents were performed onrough beds with size of 0, 4, 7.5, 12 and 15 (mm). The saline gravity currentwith three inflow discharges of 0.7, 1 and 1.3 (lit/s) and three concentrationsof 10, 16, 20 (g/lit)was flowed on slope beds from 0.05 to 2.2 steeppercentage. For estimation of frontal velocity and assessing effects ofparameters, a linear model by correlation coefficient of 0.9 and RMSE of 0.037and mean ratio deficit of less than 10% was derived. By applying of linearmodeling and linear standardization data, the efficiency index of slop,relative roughness and non-dimensional discharge (Richardson number) onprediction of non-dimension frontal velocity was estimated as 0.17,-0.50 and -0.35.

Keywords

• gravity currents
• frontal velocity
• rough bed