## 3 Results and Discussions  
### Performance of New Omni-Directional Wind-Funnel Design  
Figure 4 shows that the maximum speed of 16.24 m/s is achieved with a free-stream wind speed of 6 m/s, which leads to a 2.71-times wind-speed amplification at the venturi throat. The velocity vector and pressure distribution, as in Figures 5 and 6, also show how the importance of the length of the guide vane in the current study, preventing the early escape of the inlet air flow at the opposite end and directing sufficient speed of the airflow to enter the venturi throat, create a low-pressure region at the venturi. Table 2 shows the comparison with previous research of the performance of the proposed omni-directional wind funnel in terms of its speed ratio (SR). It is noted that the speed ratio (SR) obtained by the proposed omni-directional wind funnel design in this study outperforms the conventional design of INVELOX as well as other designs from previous research working on the performance enhancement of INVELOX. Figure 5: Velocity vector of the omni-directional wind funnel. Figure 6: Pressure distribution of the omni-directional wind funnel. Different free-stream wind speeds were tested to study their effect on the speed ratio (SR) and to understand the suitability and performance of the proposed omni-directional wind funnel in Malaysia's low wind-speed condition. The speed ratio (SR) of the proposed omni-directional wind funnel is found to be consistent and steadily increase, i.e., 2.47-2.78 over the increase in free-stream wind speeds, i.e., 1-10 m/s, as shown in Table 3. It is noted that at the maximum wind speed in Malaysia of 5.4 m/s, it is expected to achieve output wind speed at the venturi throat of the wind funnel at 14.45 m/s. Performance of Vibration Energy Harvester Located at Its Venturi Throat of New Omni-Directional Wind-Funnel Design  
Figure 7 shows a PVEH plate with dimensions 57.3 mm \(\times\) 31.8 mm \(\times\) 0.51 mm fixed at a rectangular bluff splitter body (2 mm \(\times\) 31.8 mm \(\times\) 30 mm). The first three fundamental resonant frequencies, i.e., first bending mode, twisting mode, and second bending mode under Direct Piezoelectric Effect (DPE), when it was excited by an electrodynamic shaker, were recorded at 81 Hz, 299 Hz and 478 Hz, respectively, by amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI). To study the electromechanical coupling piezoelectric materials voltage and power output in ANSYS, the conversion of the material properties of PZT or piezoelectric ceramic-based material is required. Based on the relation of Equations (5)-(7), the compliance matrix, permittivity at constant stress, and piezoelectric-strain matrix in mechanical, electrical, and electromechanical coupling disciplines, respectively, which are usually provided by PZT manufacturers, are converted to stiffness matrix, permittivity at constant strain, and piezoelectric stress matrix, as required by ANSYS. The full material properties are tabulated in Table 4.  
\[\left[s^{E}\right]=\left[c^{E}\right]^{-1} \tag{5}\] \begin{table}
\begin{tabular}{c c} \hline \hline
**Related Work on INVELOX Performance Study** & **Max Speed Ratio (SR)** \\ \hline [PERSON] and [PERSON], 2014 [8] & 1.80 \\ [PERSON]. [PERSON] et al., 2019 [10] & 1.95 \\ [PERSON] et al., 2019 [11] & 2.30 \\ [PERSON] et al., 2019 [12] & 1.90 \\ [PERSON] et al., 2020 [13] & 1.67 \\ [PERSON], 2020 [14] & 1.90 \\ [PERSON] et al., 2021 [15] & 1.74 \\ Current study & 2.71 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison with previous research of the performance of the proposed omni-directional wind funnel in terms of its speed ratio (SR). \begin{table}
\begin{tabular}{c c} \hline \hline
**Inlet Wind Speeds (m/s)** & **Max Speed Ratio (SR)** \\ \hline
1 & 2.47 \\
1.8 & 2.49 \\
2 & 2.51 \\
3 & 2.57 \\
4 & 2.62 \\
5 & 2.66 \\
5.4 & 2.68 \\
6 & 2.71 \\
7.4 & 2.72 \\
8 & 2.74 \\
10 & 2.78 \\ \hline \hline \end{tabular}
\end{table}