Below is a paragraph from an academic paper. Polish the writing to meet the academic style, improve the spelling, grammar, clarity, concision and overall readability. When necessary, rewrite the whole sentence. Furthermore, list all modification and explain the reasons to do so in markdown table. Paragraph: To simulate the air and fuel supply system accurately, the T-shape duct was utilized, encompassing the sections before and after premixing, as depicted in Fig. 2b. Figure 8 shows the sound pressure frequency spectrum of three T-shape cases (case 106-108) with the comparison to that of a straight premixed chamber case (case 38). These three T-shape ducts share the same total equivalent length (sum of LA-P and air/fuel equivalent length) as the LP in case 38. Although there are slight variations in the amplitude peaks or frequencies, the behavior of strong oscillation is highly similar among all four cases. This suggests that altering the location of fuel and air mixture has no impact on system oscillation under a constant total LP.