Numerical Modeling of Dam Break on Dry Bed

Abstract

In case of a dam break, it is important to analyze the break of the dam with numerical modeling techniques to minimize the loss of property and life in the downstream region of the dam and to take the necessary precautions during the planning of the dam. In addition, the impact of the propagation wave of existing dams on the downstream region with different scenarios can be analyzed using these methods. In this study, the numerical modeling of the dam break in the absence of any structure or flow (dry bed) on downstream of the dam is made with the ANSYS-Fluent package program using the finite volume method. In numerical modeling, Re-normalization Group k-ɛ (RNG), Shear Stress Transport (SST) and Detached Eddy Simulation (DES) models are used to solve the basic equations governing the dam break propagation wave flow. Volume of Fluid method (VOF) is used to determine of the water-air cross-section. Comparing the experimental and numerical water surface profiles obtained at different times, it was determined that the DES model is relatively more successful than the other models used. As a result of the study, it is seen that numerical models can be used safely in determining the safety measures and risk limits of the downstream region in case of a dam break.

Keywords

• Dam-break
• Numerical model
• Volume of fluid
• Detached eddy simulation

Kuru Yatakta Oluşan Baraj Yıkılmasının Sayısal Modellemesi

Abstract

Baraj yıkılmasının meydana gelmesi durumunda özellikle barajın mansap bölgesinde oluşacak mal ve can kaybının en aza indirgenmesi ve barajın planlama aşamasında gerekli önlemlerin alınması için, baraj yıkılmasının sayısal modelleme teknikleriyle analiz edilmesi önemlidir. Ayrıca, mevcut barajların yayılım dalgasının mansap bölgesine olan etkisinin farklı senaryolarla analizi de bu yöntemler kullanılarak gerçekleştirilebilmektedir. Bu çalışmada, baraj mansabında herhangi bir yapı veya akım bulunmaması durumunda (kuru yatak) gerçekleşen baraj yıkılmasının sayısal modellemesi, sonlu hacimler yöntemiyle ANSYS- Fluent paket programı kullanılarak yapılmıştır. Sayısal modellemelerde baraj yıkılması yayılım dalgası akımını idare eden temel denklemlerin çözümünde, Re-normalization Grup k-ɛ (RNG), Kayma Gerilmesi Taşınım (Shear Stress Transport -SST) ve Ayrılmış Girdap Benzetim (Detached Eddy Simulation- DES) modelleri, su hava ara kesitinin belirlenmesinde ise akışkan hacimleri yöntemi (Volume of Fluid-VOF) kullanılmıştır. Farklı zamanlarda elde edilen deneysel ve sayısal su yüzü profillerinin karşılaştırılmasından, DES modelinin kullanılan diğer modellere kıyasla nispeten daha başarılı olduğu belirlenmiştir. Çalışma sonucunda, baraj yıkılması durumunda barajların mansap bölgesinin güvenlik önlemlerinin ve risk sınırlarının belirlenmesinde, sayısal modellemelerin güvenle kullanılabileceği görülmüştür.

Keywords

• Baraj yıkılması
• Sayısal modelleme
• Akışkan hacimleri yöntemi
• Ayrılmış girdap modeli

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