Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Saric, William S.

doi:10.21236/ada388392

Cited by 3 publications

(1 citation statement)

References 35 publications

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“…Methods of actuating the membrane include mechanical displacement via the use of a loudspeaker and connecting rod [19,20] and fluidic displacement via a pressurized air chamber [21]. The former requires high maintenance and is unrealistic for practical aircraft application, while the latter requires a separate air supply and ducting.…”

Section: Membrane Actuatormentioning

confidence: 99%

Active Flow Control Systems Architectures for Civil Transport Aircraft

Jabbal

Liddle

Crowther

2010

Journal of Aircraft

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This paper considers the effect of choice of actuator technology and associated power systems architecture on the mass cost and power consumption of implementing active flow control systems on civil transport aircraft. The research method is based on the use of a mass model that includes a mass due to systems hardware and a mass due to the system energy usage. An Airbus A320 aircraft wing is used as a case-study application. The mass model parameters are based on first-principle physical analysis of electric and pneumatic power systems combined with empirical data on system hardware from existing equipment suppliers. Flow control methods include direct fluidic, electromechanical-fluidic, and electrofluidic actuator technologies. The mass cost of electrical power distribution is shown to be considerably less than that for pneumatic systems; however, this advantage is reduced by the requirement for relatively heavy electrical power management and conversion systems. A tradeoff exists between system power efficiency and the system hardware mass required to achieve this efficiency. For short-duration operation the flow control solution is driven toward lighter but less power-efficient systems, whereas for longduration operation there is benefit in considering heavier but more efficient systems. It is estimated that a practical electromechanical-fluidic system for flow separation control may have a mass up to 40% of the slat mass for a leading-edge application and 5% of flap mass for a trailing-edge application.

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Section: Membrane Actuatormentioning

confidence: 99%

Active Flow Control Systems Architectures for Civil Transport Aircraft

Jabbal

Liddle

Crowther

2010

Journal of Aircraft

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Study of Flow Controlling on LP Turbine at Different Reynolds Number

Chishty

Hamdani

Parvez

et al. 2012

Volume 1: Symposia, Parts a and B

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Active and passive techniques have been used in the past, to control flow separation. Numerous studies were published on controlling and delaying the flow separation on low pressure turbine. In this study, a single dimple (i.e. passive device) is engraved on the suction side of LP turbine cascade T106A. The main aim of this research is to find out the optimum parameters of dimple i.e. diameter (D) and depth (h) which can produce strong enough vortex that can control the flow either in transition or fully turbulent phase. Furthermore, this optimal dimple is engraved to suppress the boundary layer separation at different Reynolds number (based on the chord length and inlet velocity). The dimple of different depth and diameter are used to find the optimal depth to diameter ratio. Computational results show that the optimal ratio of depth to diameter (h/D) for dimple is 0.0845 and depth to grid boundary layer (h/δ) is 0.5152. This optimized dimple efficiently reduces the normalized loss coefficient and it is found that the negative values of shear stresses found in uncontrolled case are being removed by the dimple. After that, dimple of optimized parameters are used to suppress the laminar separation bubble at different Re∼25000, 50000 and 91000. It was noticed that the dimple did not reduce the losses at Re∼25000. But at Re∼50000, it produced such a strong vortex that reduced the normalized loss coefficient to 25%, while 5% losses were reduced at Re∼91000. It can be concluded that the optimized dimple effectively controlled flow separation and reduced normalized loss coefficient from Re 25000 to 91000. As the losses are decreased, this will increase the low pressure turbine efficiency and reduce its fuel consumption.

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Ultra High Work, High Efficiency Turbines For UAVs

Sondergaard¹

2006

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Control of Transition in Swept-Wing Boundary Layers Using MEMS Devices as Distributed Roughness

Cited by 3 publications

References 35 publications

Active Flow Control Systems Architectures for Civil Transport Aircraft

Active Flow Control Systems Architectures for Civil Transport Aircraft

Study of Flow Controlling on LP Turbine at Different Reynolds Number

Ultra High Work, High Efficiency Turbines For UAVs

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