کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1717608 | 1520084 | 2016 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Numerical prediction of nozzle flow separation: Issue of turbulence modeling
ترجمه فارسی عنوان
پیش بینی عددی جداسازی جریان نازل: مسئله مدلسازی آشفتگی
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موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی هوافضا
چکیده انگلیسی
Numerical simulation of separated flows in rocket nozzles is challenging because existing turbulence models are unable to predict it correctly. This paper addresses this issue with the Spalart-Allmaras and Shear Stress Transport (SST) eddy-viscosity models, which predict flow separation with moderate success. Their performances have been compared against experimental data for a conical and two contoured subscale nozzles. It is found that they fail to predict the separation location correctly, exhibiting sensitivity to the nozzle pressure ratio (NPR) and nozzle type. A careful assessment indicated how the model had to be tuned for better, consistent prediction. It is learnt that SST model's failure is caused by limiting of the shear stress inside boundary layer according to Bradshaw's assumption, and by over-prediction of jet spreading rate. Accordingly, SST's coefficients were empirically modified to match the experimental wall pressure data. Results confirm that accurate RANS prediction of separation depends on the correct capture of the jet spreading rate, and that it is feasible over a wide range of NPRs by modified values of the diffusion coefficients in the turbulence model.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Aerospace Science and Technology - Volume 50, March 2016, Pages 31-43
Journal: Aerospace Science and Technology - Volume 50, March 2016, Pages 31-43
نویسندگان
Yaravintelimath Allamaprabhu, B.N. Raghunandan, José A. MorÃñigo,