###### Abstract  
An alternate renewable energy source, through a piezoelectric vibration energy harvester with a bluff splitter body, could lead to higher efficiency in energy harvesting, through vortex-induced vibration at a near-resonance condition at 20 m/s high wind speed. However, wind energy is not as popular as solar energy, as the main renewable energy source in Malaysia, due to the relatively low wind speed available in the country. The INVELOX machine, introduced in 2014, was one of the most recent systems used to harvest wind power by accelerating wind speed. This omni-directional wind funnel could capture wind from all directions and tunnel it through a convergent-divergent nozzle, where the coupled bluff splitter body and piezoelectric vibration energy harvester (PVEH) are located at its venturi throat, which could lead to an increase in wind speed to fulfil the task of VIV energy harvesting. The proposed modified design is found to achieve 2.7 times the wind speed amplification at the venturi, which outperformed previously proposed designs. To achieve the optimum wind speed of 20 m/s for the coupled bluff splitter body and the PVEH plate, a free-stream wind speed of 7.4 m/s is recommended. The integration of the PVEH plate and the wind funnel is expected to harvest maximum voltage output at 20.99 V or 4.96 V, with a maximum power output of 0.82 mW at 20 m/s. wind energy; INVELOX wind funnel; vortex-induced vibration; piezoelectric vibration energy harvester 2022018 August 202218 August 20218 August 20  
In recent decades, vibration energy harvesting (VEH) received greater attention due to its potential for the renewable- and sustainable-energy supply. Inspired by vortex-induced vibration energy harvesting development as a new source of renewable energy, as proposed by the authors earlier, a T-shaped-design vibration energy harvester was proposed to enhance the vortex-induced VEH performance. It was recommended that the proposed VEH model is only suitable to be installed at high-speed flow locations, such as pipelines or exhaust fans, to generate VIV and maximum power output consistently [7]. This research proposes the design of an omni-directional wind funnel, which is installed together with the coupled bluff splitter body and PVEH plate, to fulfil the energy harvesting objective, especially in Malaysia, which has a relatively low mean wind speed. One of the most recent systems used to harvest wind power by accelerating wind speed is the INVELOX machine, introduced in 2014 by [PERSON] and [PERSON] [8]. They achieved the goal of INVELOX, as they have achieved a maximum speed ratio (SR) of 1.8 at the venturi throat. In recent years, many works have reported on the study of the INVELOX design, to further enhance its performance through some modifications and configuration changes. [PERSON] et al. studied the effects of several geometrical parameters affecting the aerodynamic performance of the INVELOX. It was found that the area contraction at the venturi, the inlet area, inlet height, and funnel height have a considerable effect on the SR. Meanwhile, the wind speed has negligible effect on the SR [9]. In 2019, [PERSON] et al. then proposed a few possible curtain designs to reduce or fully eliminate this escaping air. It is noted that the best design can lead to a 25% increase in the average wind speed inside the venturi and achieve a maximum SR of 1.95 [10]. [PERSON] et al. proposed to reduce the diameter of the venturi throat, and the wind speed at the venturi section was increased with an SR of 2.3 [11]. Meanwhile, [PERSON] et al. revealed that by increasing the assemble height, i.e., a two-storey INVELOX, it was found to be effective to reach higher performance than the conventional design, with an SR of 1.90 [12]. The effect of geometric changes in the nozzle-diffuser section was further investigated by [PERSON] et al.