Arbitrary Lagrangian–Eulerian Numerical Prediction for Local Scour Caused by Turbulent Flows

✍ Scribed by Satoru Ushijima

• Book ID: 102971366
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 535 KB
• Volume: 125
• Category: Article
• ISSN: 0021-9991
• DOI: 10.1006/jcph.1996.0080

✦ Synopsis

while local scour and three-dimensional turbulent flows were unsteadily predicted, there was still some room for A numerical prediction method has been developed for local scour on a sand bed due to turbulent flows on the basis of the arbitrary improvement owing that the coordinate system is based Lagrangian-Eulerian formulation, in which three-dimensional on Eulerian formulation.

body-fitted coordinates are properly generated for the sand bed

The arbitrary Lagrangian-Eulerian (ALE) method, iniprofile unsteadily deformed by the flows. The curvilinear coorditially proposed by Hirt [5], has been developed to solve nates are generated with reasonable accuracy by means of cubic wide-ranging moving boundary problems up to the present, spline interpolations. The equations for momentum, turbulent quansince it is advantageous compared with the Eulerian or tities, and sand concentration are discretized in a Lagrangian Lagrangian coordinate system [6]. In the present numerical scheme so as to preserve second-order accuracy with respect to time and space. The convection of the variables are evaluated with prediction method, three-dimensional non-orthogonal curthird-order accuracy, taking account of the velocity of the grid point vilinear coordinates are generated so that the coordinate caused by ALE formulation. On the other hand, the sand bed profiles lines are coincident with the deformed sand bed surface are predicted with the continuity equation for sand by evaluating on the basis of the ALE formulation. Since cubic spline the total flux consisting of the bed and suspended loads caused interpolations are utilized in the present grid generation by the tractive and convective forces of the turbulent flows. This

[7], the numerical representation of the arbitrarily deprediction method is applied to the results of a three-dimensional local scour experiment. From the comparison with the experimental formed boundary shapes and the evaluation of metric coefresults, it is verified that the sand bed profiles are satisfactorily ficients are more accurate than usual methods [8].

predicted and that the predicted results are largely improved com-

The governing equations for fluid dynamics, including pared with those based on the Eulerian coordinate system. ᮊ 1996 transport equations for turbelence energy, its dissipation Academic Press, Inc. rate and suspended loads, are discretized in a Lagrangian scheme [7], so that they can preserve second-order accuracy with respect to time and space. In addition, taking