Politeknik Dergisi 2147-9429 Gazi Üniversitesi 10.2339/politeknik.1133519 Engineering Mühendislik Açık Kaynak Kodlu SU2 Yazılımı Kullanılarak 155 mm Mühimmat İçin Gerçek ve Simülasyon Aerodinamik Katsayılarının Karşılaştırılması Comparison of Real and Simulation Aerodynamic Coefficients for 155 mm Ammunition Using Open-Source Code SU2 Software https://orcid.org/0000-0002-9884-445X Seretkaya Ahmet Ali Selçuk University, Faculty of Technology, Konya, Turkey https://orcid.org/0000-0002-6338-2718 Çalışkan Can SELCUK UNIVERSITY https://orcid.org/0000-0003-1553-581X Neşeli Süleyman SELCUK UNIVERSITY 12 16 2022 25 4 1835 1845 06 21 2022 08 10 2022 Copyright © 1998, Politeknik Dergisi 1998 Politeknik Dergisi

Bu çalışmada, 155 mm'lik bir mühimmat mermisinin hareket yörüngesi boyunca meydana gelen yoğunluk, enerji, basınç, sıcaklık değişimleri ve sürükleme katsayıları Stanford University Unstructured (SU2) hesaplamalı akış dinamiği yazılımı ile simüle edilmiştir. Simülasyonlarda Navier-Stokes (N-S) akış çözücüsünün operasyonel olarak basitleştirilmiş varyasyonları olan Reynolds-Averaged Navier-Stokes (RANS) denklemleri kullanılmıştır. Hıza dayalı Reynolds sayısı, mevcut simülasyonda 0,7 ila 2,8 arasındaki Mach (M) sayısına göre 1,65x107 ila 6,5x107 arasındaydı. Sürükleme katsayıları 0.7 M'den 2.8 M'ye kadar her Mach 0.3 artışı için ayrı ayrı elde edilmiştir. Mühimmatın geometrik çizimleri için Free Computer-Aided Design (FreeCAD) programı, ağ işlemleri için Geometry Description, Meshing, Solving, and Post-Processing (GMSH) yazılımı ve sıkıştırılabilir sonlu hacim oluşturmak için Shear Stress Transport (SST) türbülans modeli kullanılmıştır. Ayrıca, hücum açısı olarak 0 derece kullanılmıştır. Simülasyonlardan elde edilen aerodinamik katsayı yüzde değişimlerinin tahmini için R2 değerine göre geçerliliği en yüksek olan üstel denklemler oluşturulmuştur. Ayrıca hesaplanan sürükleme katsayıları gerçek değerler ile karşılaştırılmış ve aralarında iyi bir uyum olduğu gözlemlenmiştir.

In this study, density, energy, pressure, temperature changes, and drag coefficients occurring during the trajectory of movement for a 155 mm ammunition shell were simulated with the computational flow dynamics software Stanford University Unstructured (SU2). Reynolds-Averaged Navier-Stokes (RANS) equations, which are operationally simplified variations of the Navier-Stokes (N-S) flow solver, were used in the simulations. The Reynolds number based on the velocity was between 1.65x107 to 6.5x107 according to the Mach (M) number between 0.7 to 2.8 in the present simulation. The drag coefficients from 0.7 M to 2.8 M were obtained separately for each Mach 0.3 increase. The Free Computer-Aided Design (FreeCAD) program was used for geometrical drawings of the ammunition, the Geometry Description, Meshing, Solving, and Post-Processing (GMSH) software for mesh operations, and the Shear Stress Transport (SST) turbulence model to create a compressible finite volume. As well, 0 degrees was used as the angle of attack. For estimation of the aerodynamic coefficient percentage changes obtained from the simulations, exponential equations with the highest validity based on the R2 value were created. In addition, the calculated drag coefficients were compared with the actual values and a good fit was observed between them.

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