Yongliang Feng, Pierre Boivin, Jérome Jacob, Pierre Sagaut. Hybrid recursive regularized lattice Boltzmann simulation of humid air with application to meteorological flows. Physical Review E , American Physical Society (APS), 2019. ⟨hal-02265484⟩ Plus de détails...
An extended version of the hybrid recursive regularized Lattice-Boltzmann model which incorporates external force is developed to simulate humid air flows with phase change mechanisms under the Boussinesq approximation. Mass and momentum conservation equations are solved by a regu-larized lattice Boltzmann approach well suited for high Reynolds number flows, whereas the energy and humidity related equations are solved by a finite volume approach. Two options are investigated to account for cloud formation in atmospheric flow simulations. The first option considers a single conservation equation for total water and an appropriate invariant variable of temperature. In the other approach, liquid and vapor are considered via two separated equations, and phase transition is accounted for via a relaxation procedure. The obtained models are then systematically validated on four well-established benchmark problems including a double diffusive Rayleigh Bénard convection of humid air, 2D and 3D thermal moist rising bubble under convective atmospheric environment as well as a shallow cumulus convection in framework of large-eddy simulation.
Yongliang Feng, Pierre Boivin, Jérome Jacob, Pierre Sagaut. Hybrid recursive regularized lattice Boltzmann simulation of humid air with application to meteorological flows. Physical Review E , American Physical Society (APS), 2019. ⟨hal-02265484⟩
Lucie Merlier, Jérome Jacob, Pierre Sagaut. Lattice-Boltzmann large-eddy simulation of pollutant dispersion in complex urban environment with dense gas effect: Model evaluation and flow analysis. Building and Environment, Elsevier, 2019, 148, pp.634-652. ⟨10.1016/j.buildenv.2018.11.009⟩. ⟨hal-02176936⟩ Plus de détails...
The goal of this study is to assess the performance of an innovative Lattice Boltzmann (LB) - Large Eddy Simulation (LES) approach in simulating neutral and stratified pollutant dispersion in complex urban environments. Different simulations are performed for the central area of Paris, accounting for continuous neutral or non-neutral gas releases from a circular source located in both channeled or confined flows. Predicted concentrations are compared with detailed wind tunnel measurements from the MODITIC project (FFI, 2016). Results exhibit a good qualitative and quantitative agreement between numerical and experimental data for the different configurations studied. All the estimated quality metrics match acceptance criteria. In addition, it is shown that the new LBM LES approach is able to capture and highlight the key turbulent mechanisms underlying dispersion process in and above urban areas. Hence, being based on extensive and detailed simulations and quality assurance studies, this paper highlights that the developed approach is well suited to address urban dispersion issues, including accidental chemical releases and short term exposure problems. Such results are particularly valuable to support the design and use of fast response dispersion models.
Lucie Merlier, Jérome Jacob, Pierre Sagaut. Lattice-Boltzmann large-eddy simulation of pollutant dispersion in complex urban environment with dense gas effect: Model evaluation and flow analysis. Building and Environment, Elsevier, 2019, 148, pp.634-652. ⟨10.1016/j.buildenv.2018.11.009⟩. ⟨hal-02176936⟩
Yongliang Feng, Pierre Boivin, Jérome Jacob, Pierre Sagaut. Hybrid recursive regularized thermal lattice Boltzmann model for high subsonic compressible flows. Journal of Computational Physics, Elsevier, 2019, 394, pp.82-99. ⟨hal-02142837⟩ Plus de détails...
A thermal lattice Boltzmann model with a hybrid recursive regularization (HRR) collision operator is developed on standard lattices for simulation of subsonic and sonic compressible flows without shock. The approach is hybrid: mass and momentum conservation equations are solved using a lattice Boltzmann solver, while the energy conservation is solved under entropy form with a finite volume solver. The defect of Galilean invariance related to Mach number is corrected by the third order equilibrium distribution function , supplemented by an additional correcting term and hybrid recursive regularization. The proposed approach is assessed considering the simulation of i) an isentropic vortex convection, ii) a two dimensional acoustic pulse and iii) non-isothermal Gaussian pulse with Ma number in range of 0 to 1. Numerical simulations demonstrate that the flaw in Galilean invari-ance is effectively eliminated by the compressible HRR model. At last, the compressible laminar flows over flat plate at Ma number of 0.3 and 0.87, Reynolds number of 10 5 are considered to validate the capture of viscous and diffusive effects.
Yongliang Feng, Pierre Boivin, Jérome Jacob, Pierre Sagaut. Hybrid recursive regularized thermal lattice Boltzmann model for high subsonic compressible flows. Journal of Computational Physics, Elsevier, 2019, 394, pp.82-99. ⟨hal-02142837⟩
Lucie Merlier, Jérôme Jacob, Pierre Sagaut. Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects. Atmospheric Environment, Elsevier, 2018, 195, pp.89-103. ⟨10.1016/j.atmosenv.2018.09.040⟩. ⟨hal-02114676⟩ Plus de détails...
This study assesses the performance of a large eddy simulation (LES) based on the lattice Boltzmann method (LBM) in predicting near field dispersion in street canyons with tree planting. Based on a benchmark test case benefiting from wind tunnel measurements (CODASC), this study qualitatively and quantitatively discusses the prediction of traffic-induced pollutant concentration with respect to several reference studies. It also analyses the physics of the flow and concentration fields. Although the problem might seem rather simple, the flow is highlighted to be strongly three dimensional and transient. These properties enhance pollutant dispersion in the empty street canyon but air flow velocity and turbulence intensity tend to decrease in tree crowns. This effect of trees increases both mean and peak concentration levels at pedestrian level, which may be problematic in cities with dense traffic. These results show that LBM-LES is particularly well suited to study dispersion problems towards the development of more breathable cities.
Lucie Merlier, Jérôme Jacob, Pierre Sagaut. Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects. Atmospheric Environment, Elsevier, 2018, 195, pp.89-103. ⟨10.1016/j.atmosenv.2018.09.040⟩. ⟨hal-02114676⟩
Jérôme Jacob, Orestis Malaspinas, Pierre Sagaut. A new hybrid recursive regularised Bhatnagar–Gross–Krook collision model for Lattice Boltzmann method-based large eddy simulation. Journal of Turbulence, Taylor & Francis, 2018, pp.1 - 26. ⟨10.1080/14685248.2018.1540879⟩. ⟨hal-02114308⟩ Plus de détails...
A new Lattice Boltzmann collision model for large eddy simulation (LES) of weakly compressible flows is proposed. This model, referred to as the Hybrid Recursive Regularised Bhatnagar-Gross-Krook (HRR-BGK) model, is based on a modification of previously existing regularised collision models defined with the BGK Lattice Boltzmann method (LBM) framework. By hybridising the computation of the velocity gradient with an adequate Finite Difference scheme when reconstructing the non-equilibrium parts of the distribution function , a hyperviscosity term is introduced in the momentum equation, whose amplitude can be explicitly tuned via a weighting parameter. A dynamic version of the HRR-BGK is also proposed, in which the control parameter is tuned at each grid point and each time step in order to recover an arbitrarily fixed total dissipation. This new collision model is assessed for both explicit and implicit LES considering the flow around a circular cylinder at Re = 3900. The dynamic HRR-BGK is observed to yield very accurate results when equipped with Vreman's subgrid model to compute the target dissipation.
Jérôme Jacob, Orestis Malaspinas, Pierre Sagaut. A new hybrid recursive regularised Bhatnagar–Gross–Krook collision model for Lattice Boltzmann method-based large eddy simulation. Journal of Turbulence, Taylor & Francis, 2018, pp.1 - 26. ⟨10.1080/14685248.2018.1540879⟩. ⟨hal-02114308⟩
Jérôme Jacob, Pierre Sagaut. Wind comfort assessment by means of large eddy simulation with lattice Boltzmann method in full scale city area. Building and Environment, Elsevier, 2018, 139, pp.110 - 124. ⟨10.1016/j.buildenv.2018.05.015⟩. ⟨hal-02114339⟩ Plus de détails...
Large-eddy simulations based on the Lattice-Boltzmann method of the flow in a realistic, full scale urban area are performed to compare several wind comfort criteria. It is observed that popular criteria for pedestrian comfort lead to very different conclusions, due to the access to high spatio-temporal resolution data. Different mixed strategies based on the combination of several criteria are proposed and compared to enhance pedestrian wind comfort assessment in practical cases.
Jérôme Jacob, Pierre Sagaut. Wind comfort assessment by means of large eddy simulation with lattice Boltzmann method in full scale city area. Building and Environment, Elsevier, 2018, 139, pp.110 - 124. ⟨10.1016/j.buildenv.2018.05.015⟩. ⟨hal-02114339⟩
Sylvia Wilhelm, Jérôme Jacob, Pierre Sagaut. An explicit power-law-based wall model for lattice Boltzmann method–Reynolds-averaged numerical simulations of the flow around airfoils. Physics of Fluids, American Institute of Physics, 2018, 30 (6), pp.065111. ⟨10.1063/1.5031764⟩. ⟨hal-02116210⟩ Plus de détails...
In this paper, an explicit wall model based on a power-law velocity profile is proposed for the simulation of the incompressible flow around airfoils at high Reynolds numbers. This wall model is particularly suited for the wall treatment involved in Cartesian grids. Moreover, it does not require an iterative procedure for the friction velocity determination. The validation of this power-law wall model is assessed for Reynolds-averaged Navier-Stokes simulations of the flow around a two-dimensional airfoil using the lattice Boltzmann approach along with the Spalart-Allmaras turbulence model. Good results are obtained for the prediction of the aerodynamic coefficients and the pressure profiles at two Reynolds numbers and several angles of attack. The explicit power-law is thus well suited for a simplified near-wall treatment at high Reynolds numbers using Cartesian grids.
Sylvia Wilhelm, Jérôme Jacob, Pierre Sagaut. An explicit power-law-based wall model for lattice Boltzmann method–Reynolds-averaged numerical simulations of the flow around airfoils. Physics of Fluids, American Institute of Physics, 2018, 30 (6), pp.065111. ⟨10.1063/1.5031764⟩. ⟨hal-02116210⟩
