AEROACOUSTICS ANALYSIS OF CAVITY FLOW

Abstract

In this study, unsteady low Mach number flow field and aerodynamically generated noise of 2D cavity flows are investigated. In the case of 2D flow fields, different unsteady Detached Eddy Simulation (DES) turbulence models are used to observe cavity flow field. SST k–ω with two transport equations and Spalart-Allmaras with one transport equation are used to calculate near field to take in account wall effect in which DES is used. In addition to these, different discretization algorithms and approaches are employed to calculate the flow field and to account the acoustic level. Computed numerical results for cavity flow are compared and validated with an experimental measurement of low Mach numbers for the flow filed quantities and acoustic signals. All unsteady flow fields results are used to compute a cavity noise using Ffowcs Williams–Hawkings (FW-H) Acoustics Analogy and compared with experimental data. At 500 – 1500 Hz, well agreement is observed between numerical result and the experimental data which are conducted for cavity noise.

Keywords

• Cavity Flow
• Aeroacoustics
• Low Reynolds Number
• Acoustic Analogy

KAVİTE AKIŞININ AEROAKUSTİK ANALİZİ

Abstract

Bu çalışmada düşük Mach sayısı için zamana bağlı 2 boyutlu kavite akışı ve kavite boyunca akış kaynaklı aerodinamik gürültü incelenmiştir. İki boyutlu akış alanı çözümlerinde, iki farklı zamana bağlı Yeniden-Temas-Eden Girdap Benzetimi (DES) türbülans modelleri kavite akışlarını gözlemlemek için kullanılmıştır. DES ayrıklaştırmasında hibrit model olarak, iki denklemli SST k-ω ve tek taşınım denklemli Spalart-Allmaras türbülans modelleri kullanılmıştır. Bunlara ek olarak farklı sayısal ayrıklaştırma algoritma ve sayısal yöntemleri de düşük Mach sayılarında kavite akışını incelemek için kullanılmıştır. Kavite geometrisi için hesaplanan sayısal sonuçlar düşük Mach sayısı şartları altında, deneysel veriler ile hem akış alanı değişkenleri hem de akustik sinyal verileri için karşılaştırılmış ve doğrulanmıştır. Zamana bağlı akış alanı sonuçları, Ffowcs Williams–Hawkings (FW-H) Akustik Analojisi çözümleri için girdi verisi olarak kullanılıp kavite gürültü değerleri hesaplanmıştır ve deneysel veriler ile karşılaştırılmıştır. Kavite gürültüsüne ait deneysel veriler ile 500-1500 Hz frekans aralığında uyumlu sonuçlar elde edilmiştir.

Keywords

• Kavite Akışı
• Aeroakustik
• Düşük Reynolds Sayısı

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