Characterization of Steady Blowing for Flow Control in a Hump Diffuser

2004 ◽  
Author(s):  
Jonathan Luedke ◽  
Paolo Graziosi ◽  
Kevin Kirtley ◽  
Ciro Cerretelli
Keyword(s):  
Flow Control

On the transient response of the turbulent boundary layer inception in compressible flows

2018 ◽  
Vol 850 ◽  
pp. 1117-1141 ◽  
Author(s):  
J. Saavedra ◽  
G. Paniagua ◽  
S. Lavagnoli
Keyword(s):  
Boundary Layer ◽  
Flow Control ◽  
Boundary Layers ◽  
Thermal Boundary Layer ◽  
Free Stream ◽  
Test Model ◽  
Additional Time ◽  
Time Required ◽  
Momentum Boundary Layer

The behavioural characteristics of thermal boundary layer inception dictate the efficiency of heat exchangers and the operational limits of fluid machinery. The specific time required by the thermal boundary layer to be established is vital to optimize flow control strategies, as well as the thermal management of systems exposed to ephemeral phenomena, typically on the millisecond scale. This paper presents the time characterization of the momentum and thermal boundary layer development in transient turbulent compressible air flows. We present a new framework to perform such estimations based on detailed unsteady Reynolds averaged Navier–Stokes simulations that may be extended to higher fidelity simulations. First of all, the aerodynamic boundary layer initiation is described using adiabatic simulations. Additional numerical calculations were then performed by setting the isothermal wall condition to evaluate the additional time required by the thermal boundary layer to establish after the aerodynamic boundary layer reaches its steady state. Finally, full conjugate simulations were executed to compute the warm up effect of the solid during the blowdown of a hot fluid over a colder metallic test model. The transient performance of the turbulent thermal and momentum boundary layers is quantified through numerical simulations of air blowdown over a flat plate for different mainstream flow conditions. The effects of Reynolds number, free stream velocity, transient duration, test article length and free stream temperature were independently assessed, to then define a mathematical expression of the momentum boundary layer settlement. This paper presents a novel numerical correlation of the additional time required by the thermal boundary layer to be stablished after the settlement of the momentum boundary layer. The time scales of the aerodynamic and thermal boundary layers are presented as a function of relevant non-dimensional numbers, as well as the description of the response of the near wall flow to sudden free stream changes. The characterization of the boundary layer mechanisms discussed in this paper contribute to the establishment of an evidence-based foundation for advances in the field of flow control.

Characterization of a Micro Fluidic Oscillator for Flow Control

2004 ◽  
Author(s):  
James Gregory ◽  
John Sullivan ◽  
Ganesh Raman ◽  
Surya Raghu
Keyword(s):  
Flow Control ◽  
Fluidic Oscillator

Experimental Characterization of a Micro-Blower for Flow Control

2019 ◽  
Author(s):  
Maria Wu ◽  
Pierre Sullivan
Keyword(s):  
Flow Control ◽  
Turbulent Jets ◽  
Synthetic Jet ◽  
Experimental Characterization ◽  
Continuous Mode ◽  
Mean Velocity ◽  
Burst Mode ◽  
Synthetic Jet Actuator ◽  
Image Velocimetry

Abstract A compact, lightweight, low-power piezoelectric micro-blower was characterized using particle image velocimetry to determine its flow control potential. The micro-blower has been operated in continuous mode as well as in burst mode using two different actuation frequencies. The maximum mean velocity measured with the micro-blower operating in continuous mode was approximately Ūmax = 13 m/s which occurred at the centerline at an approximate stream-wise location of x/d = 4. The velocity profiles in the developed region resemble those of turbulent jets. The momentum-flux from the micro-blower in continuous mode was significantly greater than a typical synthetic jet actuator which was successfully used for flow control, indicating that the micro-blower can impart the necessary momentum to be effective for flow control. With burst mode, the results show that the micro-blower could impart an even greater momentum.

Characterization of Flow Control Device Performance with Distributed Fiber-Optic Sensors

2019 ◽  
Author(s):  
Ben Banack ◽  
Lyle H. Burke ◽  
Daniel Booy ◽  
Emeka Chineme ◽  
Marty Lastiwka ◽  
...  
Keyword(s):  
Flow Control ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Control Device ◽  
Device Performance ◽  
Flow Control Device

Characterization of Localized Arc Filament Plasma Actuators Used for High-speed Flow Control

2007 ◽  
Author(s):  
Yurii Utkin ◽  
Saurabh Keshav ◽  
Jin-Hwa Kim ◽  
Jeff Kastner ◽  
Igor Adamovich ◽  
...  
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Plasma Actuators ◽  
High Speed Flow ◽  
Speed Flow ◽  
Filament Plasma
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