Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Comparison of turbulent inflow conditions for neutral stratified atmospheric boundary layer flow
Abstract In the present work, measurements of the atmospheric boundary layer (ABL) flow, reproduced in a boundary layer wind tunnel, and large eddy simulation (LES) of the full scale ABL are presented for two ground roughness lengths. In the numerical part the ABL is simulated by utilizing the cyclic boundary conditions in downstream direction and artificial turbulence specified at the inlet. Five synthetic turbulence generation techniques are used with reviewing two input methods for the Reynolds stress. Convergence of mean velocity and second order moments is discussed for various horizontal and vertical grid refinement as well as for different roughness and wall boundary conditions of the ground. The transition of mean velocity, second order moments, stream-wise velocity spectrum and longitudinal turbulent length scale in downstream direction is analyzed. The applicability of the synthetic turbulence condition was confirmed for the LES of ABL simulations. In this way, the inflow domain length for simulations can significantly be reduced.
Highlights Five synthetic turbulence generators for LES of ABL are studied. Nearly all generators reproduce comparable results with respect to adaptation. With divergence free signal no substantial pressure fluctuations arise close to inlet. The way of specification of Reynolds stress is not essential. Integral length degrades behind the inlet and restoring requires long adaptation.
Comparison of turbulent inflow conditions for neutral stratified atmospheric boundary layer flow
Abstract In the present work, measurements of the atmospheric boundary layer (ABL) flow, reproduced in a boundary layer wind tunnel, and large eddy simulation (LES) of the full scale ABL are presented for two ground roughness lengths. In the numerical part the ABL is simulated by utilizing the cyclic boundary conditions in downstream direction and artificial turbulence specified at the inlet. Five synthetic turbulence generation techniques are used with reviewing two input methods for the Reynolds stress. Convergence of mean velocity and second order moments is discussed for various horizontal and vertical grid refinement as well as for different roughness and wall boundary conditions of the ground. The transition of mean velocity, second order moments, stream-wise velocity spectrum and longitudinal turbulent length scale in downstream direction is analyzed. The applicability of the synthetic turbulence condition was confirmed for the LES of ABL simulations. In this way, the inflow domain length for simulations can significantly be reduced.
Highlights Five synthetic turbulence generators for LES of ABL are studied. Nearly all generators reproduce comparable results with respect to adaptation. With divergence free signal no substantial pressure fluctuations arise close to inlet. The way of specification of Reynolds stress is not essential. Integral length degrades behind the inlet and restoring requires long adaptation.
Comparison of turbulent inflow conditions for neutral stratified atmospheric boundary layer flow
Plischka, Henry (Autor:in) / Michel, Simon (Autor:in) / Turnow, Johann (Autor:in) / Leitl, Bernd (Autor:in) / Kornev, Nikolai (Autor:in)
19.08.2022
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Generation of inflow turbulent boundary layer for LES computation
| British Library Conference Proceedings | 2002