Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

<table class="figure-group"><tr class="fig-image" id="a"><td><object data="https://static-preview.hindawi.com/articles/ijae/volume-2022/5353681/figures/5353681.fig.009a.svgz" name="5353681.fig.009a" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(a) </b>ECR with 4° preindex angle</td></tr><tr class="fig-image" id="b"><td><object data="https://static-preview.hindawi.com/articles/ijae/volume-2022/5353681/figures/5353681.fig.009b.svgz" name="5353681.fig.009b" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(b) </b>ECR with 6° preindex angle</td></tr><tr class="fig-image" id="c"><td><object data="https://static-preview.hindawi.com/articles/ijae/volume-2022/5353681/figures/5353681.fig.009c.svgz" name="5353681.fig.009c" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(c) </b>ECR with 8° preindex angle</td></tr></table>

<div>Sound pressure level noise contours (6<sup>th</sup>-40<sup>th</sup> blade passage frequency).</div>

International Journal of Aerospace Engineering

fig9

Figure 9

Figure 9: Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor 