Navier-Stokes computations of helicopter rotor flow fields

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Havacılık ve Uzay Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: ALİ OĞUZ YÜKSEL

Danışman: YUSUF ÖZYÖRÜK

Özet:

Helicopters are widely used for military and civilian purposes because of their unique capability of maneuvering including vertical take-off and landing. A helicopter rotor provides this capability of motion with rotating wings. Aerodynamic forces on rotor blades generate the thrust and torque. Hence, it is significant to predict pressure distributions on rotor blades in hover, climbing, descending, and forward flight, for assessing the helicopter performance. Not only this but acoustic radiation from helicopter rotors also depends on the rotor load distributions. Motivated by these points, the objective of the thesis is to carry out flow solutions of helicopter rotors in hover and forward flight. The thesis involves numerical solutions of both Euler and Reynolds-Averaged Navier-Stokes equations. Commercial software, Ansys Fluent is used together with its User Defined Function capability to handle moving meshes. To assess the success of User Defined Function capability for providing cyclic motion, comparisons with analytical blade motion are carried out. Then, numerical flow solutions over rotor blades are compared with available experimental and numerical results from literature. Results indicate good agreement. Aerodynamic load distributions on rotating blades and flow field solutions around some of the computed rotors are also used as input into a noise prediction code developed under a separate work which has been supported by the Turkish Aerospace Industry, Inc. RotaryWing Technological Center. Sound pressure levels predicted employing the flow solutions obtained in this thesis are also presented.