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U.S.P. Shet

Bio: U.S.P. Shet is an academic researcher. The author has contributed to research in topics: Noise (radio) & Shock (mechanics). The author has an hindex of 1, co-authored 1 publications receiving 3 citations.

Papers
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TL;DR: In this paper, the effects of aspect ratio, measurement plane (major vs. minor) and directivity on the sound pressure levels of rectangular and elliptic disk nozzles of various aspect ratios have been analyzed.
Abstract: Jets issuing from rectangular and elliptic disk nozzles of various aspect ratios have been studied for their noise characteristics. The overall sound pressure level and directivity were measured for these jets. The effects of aspect ratio, measurement plane (majorvs. minor-) have been analyzed. The results show that the sound pressure levels are entirely different for higher and lower aspect ratio elliptic and rectangular jets. At lower aspect ratios (AR=2:1), the noise emissions from major axis plane dominate while for higher aspect ratios jets (AR>2), the noise from minor axis plane dominate. Further, the relationship between sound pressure level and average shock-cell length is observed to be quadratic at emission angles of 30° and 90° for both rectangular and elliptic jets.

3 citations


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TL;DR: In this paper, the influence of nozzle profile on heat transfer for underexpanded impinging jets was explored and it was observed that plate shock and pressure distribution over the plate have significant influence on the local heat transfer.
Abstract: Experimental study is carried out to explore the influence of nozzle profile on heat transfer for underexpanded impinging jets. Circular and elliptical orifices are used to generate underexpanded jets for underexpantion ratio ranging from 1.25 to 2.67. The supply pressure maintained in the present study ranges from 2.36 to 5.08 times the ambient pressure. IR thermal imaging camera is used to measure surface temperature of thin foil at different nozzle to plate distances. Shadowgraph and pressure distribution are used to understand the flow structure and distribution of circular and elliptical nozzle. It is observed that plate shock and pressure distribution over the plate have significant influence on the local heat transfer. The performance of the circular orifice is far better at lower z/d. The axis switching is observed for an elliptical orifice. Correlation for local heat transfer predicts Nusselt number comparable within 15 % of experimental results.

5 citations

Journal ArticleDOI
TL;DR: In this paper, a proper scale for the average shock-cell length Ls¯ of circular and elliptic supersonic free jets is found as Ls*¯AR0.2e−0.15γMj2 and Lc*AR 0.5e− 0.11γmj2, where Lc is the nozzle throat diameter normalized by nozzle diameter Dth and Mj is the ideally expanded jet Mach number.
Abstract: A supersonic core length Lc and an average shock-cell length Ls¯ are experimentally investigated for the acoustic properties of supersonic jets. Following Kumar and Rathakrishnan [“Scaling law for supersonic core length in circular and elliptic free jets,” Phys. Fluids 33(5), 051707 (2021)], a proper scale for the average shock-cell length Ls¯ of circular and elliptic supersonic free jets is found as Ls*¯AR0.2e−0.15γMj2, where Ls*¯ is the average shock-cell length normalized by nozzle throat diameter Dth, AR is the nozzle aspect ratio, γ is the specific heat ratio, and Mj is the ideally expanded jet Mach number. The scaling law developed for Ls*¯ exhibits a close similarity with the scaling law for supersonic core length Lc*AR0.5e−0.11γMj2, where Lc* is the nozzle throat diameter normalized supersonic core length. The scaling laws Ls*¯AR0.2e−0.15γMj2 and Lc*AR0.5e−0.11γMj2 are valid across a wide range of parameters, such as γ from 1.28 to 1.6, the nozzle design Mach number Md from 1 to 2, AR from 1 to 6, and Mj corresponds to the absence of Mach reflection. Discussion conducted on the scaling laws provides important insight into the choice of AR. Furthermore, the relationship between Lc* and Ls*¯ with the intensity of shock-associated noise is also discussed; hence, new correlation functions are developed for Lc* and Ls*¯ that provide an analogous measure of the shock-associated noise.

4 citations

Journal Article
TL;DR: In this paper, the influence of tab heads on the shock train of Underexpanded jet issuing through a convergent nozzle was investigated. Tabs were attached diametrically opposite.
Abstract: This paper presents the influence of tabs on shock trains of Underexpanded jet issuing through a convergent nozzle. The shadowgraph of flow is captured to have an insight of shock structure prevailed in Underexpanded jet. Tabs were attached diametrically opposite. Tabs used in the study were elliptical and perforated elliptical. The blockage ratio was 5%. Shadowgraph pictures were captured for tabs along and normal to the flow for nozzle pressure ratios (NPRs) of 3, 4, 5, 6 and 7. It was observed that elliptical tabs, highly distorts the shock train compared to perforated elliptical tabs. However perforated elliptical tabs are more influential to reduce noise level as well as compensation for thrust loss.