Purpose The lattice Boltzmann simulation of fluid flow in partial porous geometries with curved porous-fluid interfaces has not been investigated yet. It is mainly because of the lack of a method in the lattice Boltzmann framework to model the hydrodynamic compatibility conditions at curved porous-fluid interfaces, which is required for the two-domain approach. Therefore, the purpose of this study is to develop such a method. Design/methodology/approach This research extends the non-equilibrium extrapolation lattice Boltzmann method for satisfying no-slip conditions at curved solid boundaries, to model hydrodynamic compatibility conditions at curved porous-fluid interfaces. Findings The proposed method is tested against the results available from conventional numerical methods via the problem of fluid flow through and around a porous circular cylinder in crossflow. As such, streamlines, geometrical characteristics of recirculating wakes and drag coefficient are validated for different Reynolds (5 ≤ Re ≤ 40) and Darcy (10−5 ≤ Da ≤ 5 × 10−1) numbers. It is also shown that without applying any compatibility conditions at the interface, the predicted flow structure is not satisfactory, even for a very fine mesh. This result highlights the importance of the two-domain approach for lattice Boltzmann simulation of the fluid flow in partial porous geometries with curved porous-fluid interfaces. Originality/value No research is found in the literature for applying the hydrodynamic compatibility conditions at curved porous-fluid interfaces in the lattice Boltzmann framework.

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In this paper, a multiple-relaxation-time lattice Boltzmann method (MRT LBM) is used to simulate the steady fluid flow through and around a rotating porous circular cylinder in uniform flow. This study aims at investigating the effect of Darcy number (10-6{less than or equal to}Da{less than or equal to}1×0-2), velocity ratio (0{less than or equal to}VR{less than or equal to}2), and Reynolds number (Re=20 and 40) on the Magnus lift as well as on the flow pattern and pressure coefficient inside and around the rotating porous cylinder. The results reveal that besides the enveloping and detached wakes reported in the literature for rotating solid cylinders, a new type of wake called confined wake in this study is observed in this study within the rotating porous cylinders at high Darcy numbers and velocity ratios of less than one. It is seen that the Magnus lift increases almost linearly with the velocity ratio for Da{less than or equal to}10-3, however, through curve-fitting, the rate of increase is shown to decrease with Darcy number in a non-linear manner. For Darcy numbers higher than 10-3, the Magnus lift varies non-linearly with both velocity ratio and Darcy number in such a way that, interestingly, for Re=40 and very high Darcy numbers of 7.5×10-3 and 10-2 the Magnus lift becomes negative showing a behavior called the inverse Magnus effect.