Influence of the initial conditions on velocity and acceleration parameters of gravity currents
DOI:
https://doi.org/10.26423/rctu.v8i2.608Keywords:
Richardson Number, Entrainment, Kelvin Helmholtz Instability, Acceleration Parameter, Gravity CurrentAbstract
Gravity currents are processes very common in nature and occurs when a mass of heavy fluid is discharged into a large volume of lighter fluid. They often have place on complex topographies and are therefore subject to spatial development. Previous investigations have studied the behavior of the flow according to the topography and the slope angle. The present experimental results of gravity currents moving from horizontal to an incline boundary, that is either concave or straight, combined with a variation of gate distance from 0 to 200 cm. Our study centers the attention on the impact of the ratio δBv/δIv, that is the relation between the thickness of the lower layer and the interface thickness of the current, on key parameters as acceleration or entrainment amount. It was found that δBv/δIv decreases when the angle of the slope increases θ0. Analyzing the influence of the ratio δBv/δIv over the acceleration parameter TA, we can predict that smaller the value of the ratio, the higher the value of acceleration parameter. It was demonstrated that when a gravity current with an initially non-stable interface (δBv/δIv ~1) on horizontal boundary, moves onto a sharp slope, never reaches an equilibrium state in a distance of x<12ho.
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