Abstract:A three-dimensional Lattice Boltzmann flow and scour model is developed to simulate time-dependent scour below a submarine pipeline. The proposed model presented in this paper is able to predict streamwise and spanwise propagations of scour with respect to lattice unit of time. It is evident from this study that the existence of a spiral vortex in the proximity of the span shoulder is quite noteworthy. It is revealed that the critical regime of the 2-D scour process is found to be up to one pipe diameter away in both directions from the middle of the unsupported length of pipelines. The equilibrium maximum scour depth and the shape of streamwise equilibrium scour hole compare well with the available experimental data. The speed of propagation of scour along the pipeline length maintains an almost constant rate, which is consistent with the experimental observations found in literature. In addition, it is seen that the scour slope at the shoulder region remains fairly constant throughout the whole scour process.

In this paper, a lattice Boltzmann model is developed and then parallelized employing a Compute Unified Device Architecture (CUDA) capable nVIDIA GPU platform. Numerical algorithms are developed for the solution of 3D single and two-sided non-facing lid-driven (TSNFL) cavity flow for Re = 10–1000. The algorithms are verified by solving both steady and unsteady 3D cavity and 3D TSNFL flow problems. Excellent agreement is obtained between numerical predictions and results available in literature. The results show that the CUDA-enabled LBM code is computationally efficient. It is observed that the implementation of LBM on a GPU allows at least thirty million lattice updates per second for 3-D lid driven cavity flow. Computations have been carried out for a 2-D lid driven cavity flow too. It is revealed that LBM-GPU calculation achieves 641 million lattice updates per second for the 2-D lid driven cavity flow.

No abstract

No abstract

A Lattice Boltzmann model is developed to simulate flow around a square cylinder of different roughness heights. It is evident from this study that the influences of pipe roughness on the flow parameters are quite noteworthy. It is revealed that the circumferential pipe roughness has significant influences on the hydrodynamic forces, circumferential pressure distribution, vortex shedding frequency and the formation of vortices in the vicinity of cylinder. In addition, it is seen that the orientation of the roughness elements or the density of the roughness elements does not have significant influence on the flow parameters.