Baoqing Meng | Searcharxiv

arXiv2026

High-order gas-kinetic scheme for numerical simulations of wind turbine with nacelle and tower using ALM and IBM

For the first time, the actuator line model (ALM) and the immersed boundary method (IBM) are integrated into the high-order gas-kinetic scheme (GKS) to simulate the wind turbine with the nacelle and tower. The high-order GKS is extended to the simulation of three-dimensional weakly compressible isothermal flows within a well-developed two-stage fourth-order framework. For the wind turbine, the rotor blades are represented by a group of actuator points in ALM, and the nacelle and tower are represented by a group of Lagrangian points in IBM. Both ALM and IBM are integrated through an external body force added in the momentum equation within the high-order GKS. The high-order GKS is implemented on Graphics Processing Units (GPU) to achieve the parallel computing capabilities for the large-scale simulation of turbulent wakes. Turbulent channel flow and turbulent circular cylinder flow are firstly simulated to validate the numerical accuracy of weakly compressible high-order GKS. The NREL 5 MW reference wind turbine is simulated using ALM without the nacelle and tower. Furthermore, the NTNU Blind Test 1 wind turbine is simulated with nacelle and tower using IBM. The current method yields the periodic power and thrust coefficients of the rotor blade due to the blade-tower interactions, while the steady coefficients are obtained when the tower is omitted. Compared to the turbine wakes without the tower, the interaction between tower vortex and tip vortex causes an earlier transition. The high-order GKS with ALM and IBM also well predicts the asymmetric mean flows of turbine wake, including the time-averaged streamwise velocity and turbulent kinetic energy, which are in good agreement with NTNU experimental data. The multiple-GPU enabled high-order GKS integrated with ALM and IBM offers an accurate and efficient approach for realistic wind turbine simulations.

physics.flu-dyn↗

arXiv2025

A high-fidelity and efficient framework for point-particle direct numerical simulation based on multi-block overset grids

In this work, we present a high-fidelity and efficient point-particle direct numerical simulation framework based on a multi-block overset curvilinear grid system, enabling large-scale Lagrangian particle tracking in complex geometries with high-order accuracy and low computational cost. To handle the multi-domain topological challenges inherent in such configurations, we develop an efficient particle storage and redistribution framework leveraging overset grid techniques. In particular, two optimization strategies have been proposed for particle redistribution: one is an innovative inter-block mapping within overlapping zones, and the other is a fast search-locate algorithm based on particle velocity. Together, these approaches significantly reduce the particle tracking overhead, especially for particles passing through interfaces between overlapping grid blocks. Moreover, the accuracy and robustness of the present framework are rigorously validated through various cases, including massless particle trajectories, one- and two-way coupled simulations. Specifically, we demonstrate the framework's applicability to the direct numerical simulation of particle-laden flow in a linear compressor cascade at engine-relevant conditions, showcasing its capability to resolve complex particle dynamics in turbomachinery configurations with low computational costs.

physics.flu-dyn↗