Effect of plate inclination on the noise of impinging jets

Dhamanekar, Abhijit; Srinivasan, K.

doi:10.1016/j.apacoust.2017.06.002

Cited by 6 publications

(2 citation statements)

References 23 publications

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“…Salehian and Mankbadi 35 showed that water injection from the ground plane reduces the far-field sound by about 2–3 dB at low frequencies (up to 4 kHz). Dhamanekar and Srinivasan 36 studied the flow and acoustic variation due to the jet impinging on inclined plates and found the reduction or enhancement of the acoustic radiation depends on the noise location measurement, standoff distance, and nozzle pressure ratio. Whereas, Qi et.…”

Section: Introduction and State Of The Artmentioning

confidence: 99%

Acoustic characteristics of jets impinging on permeable plates

Dhamanekar,

Srinivasan

2023

International Journal of Aeroacoustics

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This article explores the acoustic characteristics and the relevant flow features of jets impinging on permeable plates. Noise generated due to the interaction of the jet with permeable plates is compared with jets impinging on an impermeable plate and the corresponding free jet. This study systematically measures various parameters, including pore size, porosity, and pressure drop, to precisely quantify the permeability of the plates using the Forchheimer equation. The focus is on investigating the impact of permeability on noise reduction. An acoustic study is performed by carrying out blow-up and blow-down tests to find the effect of permeability at different nozzle pressure ratios and different nozzle-plate spacings. An extensive directivity study is conducted to find the directionality of acoustic emissions and calculate acoustic power. It is found that the overall sound pressure level is lower for the jets impinging on the permeable plates compared to the impermeable plates in subsonic cases. It is also observed that the insertion of the permeable plates in supersonic jets generates less noise compared to the corresponding free jet. It is found that most of the tones are absent in the case of permeable plates for supersonic jets, whereas the tones are present with lesser amplitude compared to jets impinging on impermeable plates for subsonic and transonic jets. Finally, flow measurement and flow visualization studies are carried out to understand the flow physics responsible for the noise variance. This study illuminates that the passage of flow through the porous plate results in the reduction of wall-jet velocities, thereby suppressing the turbulent mixing noise. The absence of shock oscillations in front of the permeable plate is identified as the cause of the mitigation of impinging tones.

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Section: Introduction and State Of The Artmentioning

confidence: 99%

Acoustic characteristics of jets impinging on permeable plates

Dhamanekar,

Srinivasan

2023

International Journal of Aeroacoustics

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“…Çarpan jetler, hem günümüzde aktif olarak uygulama alanı bulan hem de geleceğe yönelik beklentileri karşılama potansiyeline sahip modern ve yenilikçi ısıl kontrol yöntemlerinden biridir. Endüstrideki bazı uygulama alanları; elektronik ekipmanların soğutulması (Oztekin vd., 2012), uçak kanatlarında buzlanmayı önleyen sistemler (Yu vd., 2014), gaz türbini kanatlarının ve yanma odalarının dış duvarlarının soğutulması (Rim vd., 2016), tekstil ürünleri ve kağıtların kurutulması (Fenot ve Doricnac, 2016), camın tavlanması (Dhamanekar ve Srinivasan, 2017) olarak örneklendirilebilir. Hidrodinamik açıdan bir çarpan jet; serbest jet bölgesi, çarpma bölgesi ve duvar jeti bölgesi olmak üzere üç farklı bölgeden oluşmaktadır (Nuntadusit vd., 2012;Ahmed vd., 2016).…”

Section: Introductionunclassified

Çarpan Eş Eksenli Bir Hava Jetinde Debi Oranının Akış Karakteristikleri Üzerine Etkisinin Deneysel Olarak İncelenmesi

Markal¹

2018

Gümüşhane Üniversitesi Fen Bilimleri Enstitüsü Dergisi

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ÖzBu çalışmada, dairesel ve halkasal eş eksenli akış pasajlarına sahip bir lüleden çıkarak dairesel bir plaka üzerine çarpan jetin hidrodinamik karakteristikleri deneysel olarak incelenmiştir. Deneyler üç farklı Reynolds sayısında (Re = 6688, 9364 ve 12039), beş farklı debi oranında (Q* = 0, 0.2, 0.5, 0.8 ve 1.0) ve tek bir boyutsuz lüle-plaka uzaklığında (H* = 0.8) gerçekleştirilmiştir. Belirtilen çalışma parametreleri için boyutsuz basınç katsayısının (C P ) çarpma plakası üzerinde merkez hattı boyunca dağılımı elde edilmiştir. İncelenen tüm Reynolds sayılarında, Q* = 0, 0.2 ve 0.5 değerleri için durma noktası çarpma plakası merkezinde oluşmakta ve ilgili noktaya ait basınç değerleri artan Q* ile azalmaktadır. Q* = 0.8 ve 1.0 ise birbirine benzer davranış göstermekte olup, bu şartlar altında çoklu durma noktaları oluşmaktadır.Anahtar kelimeler: Basınç dağılımı, Debi oranı, Eş eksenli çarpan jet AbstractIn this study, hydrodynamic characteristics of a jet issuing from a nozzle with concentric circular and annular flow passages are investigated experimentally. Experiments are conducted for different Reynolds number (Re = 6688, 9364 and 12039) and flow rate ratio (Q* = 0, 0.2, 0.5, 0.8 and 1.0) at a constant dimensionless nozzle-to-plate distance (H* = 0.8). For the relevant test parameters, the distribution of the dimensionless pressure coefficient (C P ) through the centerline of the impingement plate is obtained. For all the Reynolds numbers and the values of Q* = 0, 0.2 and 0.5, the stagnation point formed at the center of the impingement plate, and the relevant pressure values for this point decreases with increasing Q*. On the contrary, Q* = 0.8 and 1.0 shows similar behaviors (for each other) in which multiple stagnation points occur.

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