S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Mechanical Aerospace Engineering (기계항공공학부) Theses (Ph.D. / Sc.D._기계항공공학부)
실속 조건에서 Synthetic Jet 능동 유동 제어에 관한 실험적 연구
Experimental Study on Active Flow Control of Synthetic Jet in Stalled Condition
- 공과대학 기계항공공학부
- Issue Date
- 서울대학교 대학원
- 학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 2. 김종암.
- This paper presents experimental investigations of the characteristics of synthetic jets with a circular exit array. The flow characteristics of piezoelectrically driven synthetic jets with a circular exit array were investigated under various flow conditions. Step-by-step experiments were conducted to find an improved configuration of a circular exit array while some parameters were held constant, in this case the oscillation frequency, input voltage, and exit area. Comparative studies were conducted to compare a quiescent condition, a forced separated flow, and separated flows over high angles of attack. For the quiescent condition, jet characteristics depending on the hole perimeter and oscillation frequency were compared by measuring velocity profiles by means of hot-wire anemometry. For the forced separated flow, pressure distributions on an inclined flat plate were examined while changing the parameters of the hole diameter, hole gap, type of synthetic jet array, and oscillation phase. Experimental results were then analyzed with a help of the computed vortical structures in the quiescent and forced separated-flow conditions. Based on the comparisons, a proper range of design parameters for an improved circular exit array was obtained, showing that the circular exit array based on the design parameters provided better performance in terms of separation control. For separated flows over an airfoil and a blended wing body configuration at high angles of attack, the flow control performance of the proposed synthetic jets was verified by measuring the aerodynamic coefficients. Based on various comparisons, synthetic jets with the improved circular exit array were found to be effective for control of the flow separation phenomenon.