Effect of a hump on the stability of subsonic boundary layers over an airfoil
Abstract The effect of a hump on the stability of subsonic boundary layers over an airfoil is investigated. The mean flow is calculated using an interacting boundary-layer solver which accounts or strong viscous-inviscid interaction and separation bubbles. The two-dimensional stability of the calculated two-dimensional mean flows is determined. The growth rates are integrated along a prescribed path to yield the amplification factor (i.e. N-factor), which is used to predict transition from laminar to turbulent flow. The analysis is performed for different heights and locations of the hump and for different Mach numbers. The results show that increasing the Mach number enhances separation, which partially offsets the stabilizing influence of compressibility. The most dangerous frequency decreases as the Mach number increases for a fixed hump location or the hump is moved downstream for a fixed Mach number. Moreover, the amplification factor increases as the hump height increases and the peak amplification factor increases and moves further downstream as the hump is moved downstream. The influence of suction and heat-transfer strips on controlling the destabilizing influence of the hump is investigated. The results show that cooling and suction strips stabilize the flow and therefore delay transition from laminar to turbulent flow, whereas, a heating strip destabilizes the flow. Applying suction through multiple strips can be as effective as suction through a single strip. Also the total flow rate required using multiple strips may be less than that required using a single strip. Moreover, cooling through multiple strips is as effective as cooling through a single strip. We investigate optimal locations of suction and cooling strips for a certain hump location.
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기