RESEARCH ON THE UNCERTAINTY ANALYSIS IN CFD SIMULATION OF THE DREDGING DUSTPAN

摘要

The main focus of this paper is on the uncertainty analysis methodology and procedure in CFD recommended by 22nd ITTC and the benchmark database for the verification and validation of the results of dredging dustpan's inlet and outlet cross-section velocity ratio coefficient v_(iur). Compared with the previous uncertainty analysis of CFD focused on the fluid grid-convergence in the steady flow, which is less to consider other factors that may affect the accuracy of the results of numerical simulation, this study compensates for this deficiency and implements the grid-convergence and time-step-size-convergence studies respectively by using three types of grids and time step sizes with refinement ratio under the condition of unsteady flow. Through confirming the validity of CFD uncertainty analysis, the agreement between the numerical simulation correction values from the grid-convergence and time-step-size-convergence and the benchmark test data is found to be quite satisfactory. The results obtained in this study have shown that it is indispensable to carry out the time-step-size-convergence studies for CFD uncertainty analysis during the unsteady flow calculation because the numerical simulation errors respectively caused by the grid and time-step-size in the convergence study have the same order of magnitude. In further the present study of simultaneously conducting both grid-convergence and time-step-size-convergence is demonstrated efficient and effective in the CFD uncertainty analysis.