Author(s): Arthur Hajaali; Zhihua Xie; Pablo Ouro; Thorsten Stoesser

Linked Author(s): Thorsten Stoesser, Pablo Ouro, Zhihua Xie

Keywords: No keywords

Abstract: The present study aims at quantifying the accuracy of two such IBM methods, one is the direct forcing.(DF) approach as implemented by Kara et al. and the other is the Cartesian cut-cell (CC) approach as implemented by Xie. Two LES employing a DF and a CC approach, respectively are performed for turbulent open channel flows over fractal surfaces chosen to correspond approximately to gravel bed-type roughness. The roughness Reynolds number of the flow, based on shear velocity, u*, and roughness height, k, is approx. 255 and the relative submergence of the flow, defined as the ratio of channel depth to maximum roughness height, k, is 12. Double-averaging of the mean and fluctuating velocity fields is applied to obtain vertical distributions of the turbulence statistics and similarities and differences in the flow and turbulence statistics of the two methods are revealed and discussed.

DOI: https://doi.org/10.3850/978-981-11-2731-1_342-cd

Year: 2018