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Numerical studies of flapping foil flow energy harvester in wall, foil structure and arrangement effects based on an adaptive immersed boundary-lattice Boltzmann flux solver were performed. An adaptive lattice Boltzmann method (LBM) is employed for simulating the flow field accurately and efficiently on a moving Cartesian grid. By enforcing the speed of the Cartesian grid the same as the translational velocity of the rigid body, it is able to study the moving object in a large flow domain. It considerably reduces the number of grid points and computational efforts. The interaction between the fluid and the moving boundary is made by the implicit immersed boundary method with a smoothed discrete delta function to accurately satisfy the no-slip boundary condition and suppress the non-physical force oscillations. First, the flows over a transversely oscillating circular cylinder and a flapping foil in ground effect were simulated for validating the effectivity and the accuracy. Then, the wall, foil structure and arrangement effects on the performances of flapping foil were numerically investigated. The wall is single or double, and is represented by plates with different sharps and slopes. Due to the improvements of the sharps of the wall and foil structure as well as the foil arrangement, the evolution law of vortex topology around the flapping foil was better at enhance the hydrodynamic force and its consistency with the foil motions, the performance of the flapping foil is greatly changed.