Effect of Local Grid Refinement on Performance of Scale-Resolving Models for Simulation of Complex External Flows

Abstract

Numerical simulations are crucial for fast and accurate estimations of the flow characteristics in many engineering applications such as atmospheric boundary layers around buildings, external aerodynamics around vehicles, and pollutant dispersion. In the simulation of flow over urban-like obstacles, it is crucial to accurately resolve the flow characteristics with reasonable computational cost. Therefore, Large Eddy Simulations on non-uniform grids are usually employed. However, an undesirable accumulation of energy at grid-refinement interfaces was observed in previous studies using non-uniform grids. This phenomenon induced oscillations in the spanwise velocity component, mainly on fine-to-coarse grid interfaces. In this study, the two challenging test cases of flow over urban-like cubes and flow over a 3-D circular cylinder were simulated using three different scale-resolving turbulence models. Simulations were performed on uniform coarse and fine grids on one hand, and a non-uniform grid on the other, to assess the effect of mesh density and mesh interfaces on the models’ performance. Overall, the proposed One-Equation Scale-Adaptive Simulation (One-Equation SAS) showed the least deviation from the experimental results in both tested cases and on all grid sizes and types when compared to the Shear Stress Transport-Improved Delayed Detached Eddy Simulation (IDDES) and the Algebraic Wall-Modeled Large Eddy Simulation (WMLES).

A Two-Stage Multi-Agent EV Charging Coordination Scheme for Maximizing Grid Performance and Customer Satisfaction

“…Due to the uncertainty of the arrival and departure of EVs and their increasing penetration into the power grid, it is difficult for the grid operator to maintain grid operational efficiency and achieve the load satisfaction of every individual EV customer in a shorter lead time. It is essential in real-world problems to achieve the desired objectives with reasonable computational effort [ 21 ]. If the problem is divided into two stages instead of solved as one unit, we can achieve our objectives and shorten the algorithm execution time.…”

Research on precise and standardized numerical simulation strategy for vehicle aerodynamics

“…Based on the improved delayed detachment simulation (IDDES) model, Wang et al (2018) studied the effect of relative ground motion on a slipstream with three different ground/ wheel configurations. Combined with the elliptical equation, an algebraic mesh generation method was introduced to construct a high-quality mesh for the simulation of vehicle aerodynamics (ElCheikh and ElKhoury, 2019;Fu et al, 2020) conducted a comparative analysis of the influence of ground boundary conditions on the simulation accuracy of airflow around a vehicle. The effect of an air deflector on the aerodynamic drag of a truck has been studied using a hybrid grid technique (Li et al, 2008).…”