Experimental and Numerical Analysis of Supercritical Open Channel Flow Downstream of a Sill

Öz

The velocity field of supercritical open channel flow downstream of a sill is measured using Laser Doppler Anemometry (LDA). Basic equations of the problem are solved by ANSYS-Fluent program package based on finite volume method for the flow case having the same experimental conditions. In the numerical simulations, Realizable k-ε turbulence closure model based on the Reynolds Average Navier Stokes Equations and Large Eddy Simulation model are used for the simulation of turbulence, and the flow profile is computed using Volume of Fluid Method. Computational results for velocities and free surface profiles are compared with measured data. Experimental validations of the turbulence models show that the Realizable k-ε turbulence model is more successful than LES in predicting the velocity field and free surface profiles under the present flow conditions.

Anahtar Kelimeler

• Velocity profile,Supercritical open channel flow,LES,RANS,Free surface profile,VOF

Eşik Mansabındaki Kritik Üstü Açık Kanal Akımının Deneysel ve Sayısal Analizi

Öz

Açık kanalda eşik sonrası oluşan kritik üstü açık kanal akımının hız alanı, laboratuvar ortamında Lazer Doppler Anemometresi (LDA) ile ölçülmüş ve deney ile aynı koşullardaki akım için temel denklemler, sonlu hacimler yöntemine dayalı ANSYS-Fluent paket programı ile üç boyutlu olarak çözülmüştür. Sayısal hesaplamalarda, Reynolds Ortalamalı Navier Stokes (RANS) denklemlerine dayalı Realizable k-ε türbülans kapatma modeli ve Large Eddy Simülasyon (LES) modeli kullanılmış, su yüzü profili Akışkan Hacimleri Yöntemi ile hesaplanmıştır. Sayısal modellerden elde edilen akım hızları ve su yüzü profilleri deneysel ölçümlerle karşılaştırılmıştır. Farklı iki modelin deneysel olarak doğrulanması amacıyla yapılan karşılaştırmalarda, Realizable k- türbülans kapatma modelinin, hız alanının hesaplanmasında ve su yüzünün belirlenmesinde LES modeline göre daha başarılı olduğu görülmüştür.

Anahtar Kelimeler

• Hız profili,Kritik üstü akım,LES,RANS,Su yüzü profili,VOF

Kaynakça

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