The three-dimensional visualization of flow and screech-tone emission from an underexpanded circular jet is first investigated experimentally using high-speed cross-schlieren imaging and microphone measurements in the...The three-dimensional visualization of flow and screech-tone emission from an underexpanded circular jet is first investigated experimentally using high-speed cross-schlieren imaging and microphone measurements in the cross-sectional planes along the jet axis. This experimental technique allows the visualization of the shock-cell structure, directivity of sound intensity, and frequency spectrum in the cross-sectional planes of the screeching jet. The high-speed cross-schlieren observation of the screeching jet shows the occurrence of an asymmetrical shock-cell structure that is generated by the flapping mode in the screeching jet. This contributes to the generation of a screech tone propagating upstream along the jet axis and non-uniform sound intensities around the jet in circumferential direction. These observations by high-speed cross</span><span style="white-space:normal;font-size:10pt;font-family:"">-</span><span style="white-space:normal;font-size:10pt;font-family:"">schlieren imaging were validated by the microphone measurements.展开更多
文摘The three-dimensional visualization of flow and screech-tone emission from an underexpanded circular jet is first investigated experimentally using high-speed cross-schlieren imaging and microphone measurements in the cross-sectional planes along the jet axis. This experimental technique allows the visualization of the shock-cell structure, directivity of sound intensity, and frequency spectrum in the cross-sectional planes of the screeching jet. The high-speed cross-schlieren observation of the screeching jet shows the occurrence of an asymmetrical shock-cell structure that is generated by the flapping mode in the screeching jet. This contributes to the generation of a screech tone propagating upstream along the jet axis and non-uniform sound intensities around the jet in circumferential direction. These observations by high-speed cross</span><span style="white-space:normal;font-size:10pt;font-family:"">-</span><span style="white-space:normal;font-size:10pt;font-family:"">schlieren imaging were validated by the microphone measurements.
