Necati AĞIRALİOĞLU, Fatih ÜNEŞ

Yoğun dalmış hazne akımlarının matematiksel modelle incelenmesi

Baraj haznesine giren su ile haznedeki su arasındaki yoğunluk farkı, sıcaklık farklılığından yada askı maddesi veya çözülmüş madde konsantrasyonu farklılığından oluşabilir. Bu çalışmada, sadece sıcaklık farklılığından oluşan yoğunluk akımları, tabanı eğimli bir hazne boyunca, iki boyutlu matematik model kullanılarak incelenmiştir. Kararsız akım durumunda, süreklilik, hareket, enerji, ve türbülans model denklemleri kartezyen koordinat sisteminde çıkarılmıştır. Bu denklemler hazne akımının başlangıç ve sınır şartları için çözülmüştür.Akım alanında oluşan hızlar, sıcaklıklar, karışım oranları, dalma noktaları ve dalma derinlikleri, kontrol hacim kavramı ve sonlu farklar metodu kullanılarak Fluent 5.3 programı ile belirlenmiştir. Sonuçlar daha önce yapılan matematik model sonuçları ve deney ölçmeleri ile karşılaştırılmış ve grafikler halinde boyutsuz olarak değerlendirtmiştir.

Investigation of density plunging reservoir flow using mathematical modelling

Density difference between inflowing and ambient waters may be due to a difference in temperature or concentration of dissolved or suspended substance. In this study, density flow, which will be occurring only due to a difference in temperature in a reservoir with a bottom slope is investigated by using two dimensional mathematical model. In the present model, nonlinear and unsteady continuity, momentum, energy and turbulence model equations are formulated in Cartesian coordinates. For the turbulence viscosity, $k-varepsilon$ turbulence model is used with an extension to include production or destruction of turbulent kinetic energy. The equations of the model are solved based on the initial and boundary conditions of the dam reservoir flow for a range of bottom slopes. Understanding of these flows is important from the point of view of water quality modeling, reservoir sedimentation studies, effluent mixing analyses and habitat in reservoirs. Velocities, temperatures, mixing rates as well as plunging points and plunging depths are determined using control volume concept and finite difference method using Fluent 5.3 software program. The results are compared with those of previous mathematical and experimental studies, and evaluated graphically in nondimensional form.

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