Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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Subject: search.filters.subject.Flow Control

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Role of Partial Flexibility on Flow Evolution and Aerodynamic Power Efficiency Over a Turbine Blade Airfoil
    (MDPI, 2024-07-11) Koca, Kemal; Genc, Mustafa Serdar
    In this study, the aerodynamic performance of a cambered wind turbine airfoil with a partially flexible membrane material on its suction surface was examined experimentally across various angles of attack and Reynolds numbers. It encompassed physical explanation at the pre/post-stall regions. The results of particle image velocimetry revealed that the laminar separation bubble was diminished or even suppressed when a local flexible membrane material was employed on the suction surface of the wind turbine blade close to the leading edge. The results of the deformation measurement indicated that the membrane had a range of flow modes. This showed that the distribution of aerodynamic fluctuations due to the presence of LSB-induced vortices was reduced. This also led to a narrower wake region occurring. Aerodynamic performance improved and aerodynamic vibration significantly lowered, particularly at the post-stall zone, according to the results of the aerodynamic force measurement. In addition to the lift force, the drag force was enormously reduced, corroborating and matching well with the results of PIV and deformation measurements. Consequently, significant benefits for a turbine blade were notably observed, including aerodynamic performance enhancement, increased aerodynamic power efficiency, and reduced aerodynamic vibration.
  • Article
    Citation - WoS: 19
    Citation - Scopus: 21
    Investigation of the Effect of Hidden Vortex Generator-Flap Integrated Mechanism Revealed in Low Velocities on Wind Turbine Blade Flow
    (Pergamon-Elsevier Science Ltd, 2023-07) Ozden, Mustafa; Genc, Mustafa Serdar; Koca, Kemal
    In this study, the flap and vortex generator (VG) mechanisms which were employed separately in aircraft were used as integrated first in literature. In this mechanism, the flap motion triggered and activated the VGs when it was needed at low speeds. Thus, this flap mechanism eliminated the unnecessary drag force generation when VGs were not needed. Numerical simulations which were validated with experimental data were employed in the study. In the first step, the flow characteristics formed on the S809 airfoil with 4 different flap angles ( beta = 30 degrees, 20 degrees, 10 degrees, 0 degrees) were investigated without the VG. Then, those flow structures formed on the S809 airfoil with both flap and VG were examined under the same conditions. According to the results, utilizing flap and VGs together had a positive impact at low wind speeds. Moreover, due to the flap and vortex generator integrated mechanism closed up to be not unnecessary drag formation at high wind speeds, thus those structures increased further to the positive effect with the increasing wind velocity. In terms of energy output, it was shown that this novel idea provided more energy output in this study.
  • Conference Object
    Citation - Scopus: 154
    A Review of Fluidic Oscillator Development and Application for Flow Control
    (2013) Gregory, James W.; Tomac, Mehmet N.
    This review provides a detailed discussion of the historical development of fluidic oscillators and their application to flow control. Fluidic oscillators were initially developed in the 1960's for a variety of applications, and have seen resurgent interest for their suitability for modern flow control applications. The devices produce an oscillating jet of fluid over a wide fan angle and have no moving parts, making them an attractive actuator concept. This review aims to highlight the most important historical papers of relevance to modern fluidic oscillator development. The reviewed works will extend from the early 1960's to the most recent investigations, with a focus on the fundamental operating mechanisms of fluidic oscillators. The authors present this review as a short synopsis of fluidic oscillators for flow control, while a more comprehensive review will be submitted for archival publication in the near future. © 2013 Elsevier B.V., All rights reserved.