Flow topology and wake calming mechanisms in a hybrid wind–solar system

Abstract

This study investigates the coupled aerodynamic interference between a vertical-axis wind turbine (VAWT) array and a parabolic trough condenser (TC) array in a hybrid wind–solar system. Combining wind tunnel testing and high-fidelity computational fluid dynamics with a hybrid RNG (renormalization group) k–ε/LES (large eddy simulation) approach, we analyze the three-dimensional wind field under varying TC elevation angles (30°, 60°, and 90°). Results show that the TC angle governs the internal flow regime: A low angle (30°) induces strong ground-channeling acceleration but high spatial heterogeneity, while a high angle (90°) yields a more uniform flow with a concentrated wake. Crucially, a universal “wake calming effect” is identified, but with a redefined physical mechanism. Topological analysis (Q-criterion) reveals a “structural breakdown” phenomenon, where the upstream VAWT wake shatters the large-scale coherent gap vortices of the TC array into disjointed eddies. Power spectral density quantitatively confirms that while the dominant low-frequency shedding is suppressed, the turbulent energy is redistributed to broadband scales (spectral broadening). This process facilitates momentum injection from the freestream into the stagnation zones, effectively transforming the VAWT from a passive obstacle into an active flow stabilizer. This study reveals the fluid-mechanic coupling mechanisms, providing critical insights for optimizing hybrid system layouts to mitigate aerodynamic impacts and improve overall performance and safety.