Kısmen Batık Bir Bariyerin Su Dalgaları ile Etkileşiminin Açık Kaynaklı Hesaplamalı Akışkanlar Dinamiği ile İncelenmesi

Bu çalışmada, düşey, düzlemsel ve rijit bir bariyerin, sabit genlik ve frekansa sahip su dalgaları ile etkileşimi problemi ele alınmıştır. Öncelikle problemin lineer dalga teorisi altında analitik çözümüne ilişkin yöntem verilmiştir. Daha sonra bir açık kaynaklı hesaplamalı akışkanlar dinamiği yazılımı olan OpenFOAM kapsamındaki modüller aracılığıyla problemin sayısal çözümü gerçekleştirilmiştir. Ön aşama olarak, iki boyutlu sayısal dalga kanalı testleri ile, bu modüllerin dalga oluşturma ve sönümleme gibi özellikleri sınanmıştır. Analitik çözümlere kıyasla görülen en yüksek hata %1 olarak bulunmuştur. Belirlenen ağ ve çözücü özellikleri, batık bariyer probleminin modellenmesinde kullanılmıştır. Bariyerden yansıyan ve üreteçten çıkan dalgalar, lineer dalga teorisine dayalı olarak ayrıştırılmış, böylece yansıma ve iletilme katsayıları hesaplanmıştır. Çeşitli dalga frekansları için bulunan sonuçlar, hem analitik çözümle hem de literatürde yer alan deneysel sonuçlarla karşılaştırmalı olarak değerlendirildiğinde, nicel ve nitel olarak yüksek uyum yakalandığı görülmüştür. Ayrıca, viskozite etkilerinin de hesaba katılmasıyla, lineer teoride ihmal edilen enerji kayıpları da belirlenmiş; bu kayıpların başlıca nedeninin bariyer ucundaki çevri oluşumu olduğu görülmüştür. Bir kısmen batık bariyer uygulaması olan salınan su sütunu ön duvarındaki enerji kayıplarının, salınan su sütunu hidrodinamik verimi üzerindeki etkisi tartışılmıştır.

Investigating the Interaction of a Partially Submerged Barrier with Water Waves Using Open-Source Computational Fluid Dynamics

The interaction of a vertical, flat, rigid barrier with monochromatic water waves of constant amplitude is considered in this study. The method for the analytical solution to the problem under the assumptions of linear wave theory is introduced. This is followed by the numerical solution to the problem using the modules under the open-source computational fluid dynamics code OpenFOAM. As an initial stage, twodimensional, numerical wave flume tests are carried out where the wave generation and absorbing features are tested. Maximum error relative to analytical solutions is found to be 1%. Grid and solver properties to be used for the submerged barrier problem are determined at this stage. The reflected and incident wave signals are decomposed with an approach based on the linearized theory. Results obtained for several frequencies are found to be in good agreement with the analytical computations performed here and the experimental results obtained by other researchers. Taking the viscosity effects into account, the amount of energy loss which is neglected in the linearized thory is computed. The vortex formation at the tip is found to be the primary reason for this loss. Effects of the energy losses of the oscillating water column front wall which is a partially submerged barrier application, on the the oscillating water column hydrodynamic efficiency are investigated.

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