Langley Research Center Turbulence Modeling Resource

Exp: Round Synthetic Jets for Separation Control on 2-D Curved Backward-Facing Step

Return to: Data from Experiments - Intro Page

The data on this page were provided by Dr. Shanying Zhang and Dr. Shan Zhong.

These experimental data are for turbulent boundary layer separation control over a 2-D ramp using round synthetic jet actuators, causing delayed flow separation. The data were taken in the Boundary Layer Wind Tunnel (BLWT) at the University of Manchester. Several different operating conditions were measured using stereo particle image velocimetry (PIV) and three-component laser Doppler anemometry (LDA). Detailed experimentation set-up can be found in:

• Zhong, S., Zhang, S., 2013, "Further Examination of the Mechanism of Round Synthetic Jets in Delaying Turbulent Flow Separation." Flow, Turbulence and Combustion, 91(1), 177-208, https://doi.org/10.1007/s10494-013-9469-5.
• Zhang, S., Zhong, S., 2011, "Turbulent Flow Separation Control Over a Two-Dimensional Ramp Using Synthetic Jets," AIAA J. 49(12), 2637-2649, https://doi.org/10.2514/1.J051046.

These experimental data were produced in a joint research program between the University of Manchester and Imperial College, with Imperial College producing the LES results, as described on the LES: 2-D Curved Backward-Facing Step page (the LES is provided only for the baseline case without flow control), and Manchester providing the physical measurements described here.

Some relevant information is given here, but the interested reader is referred to the above publications for complete details:

• Ramp-down height (h)= 31.5 mm
• Ramp-down length = 90.9 mm
• Ramp-down span = 1200 mm (spans the test section)
• Working section height = 300 mm
• Free stream velocity = 6.5 m/s

The geometry file describing ramp down session is here: Ramp-down Definition.

The geometry of the round synthetic jet is as follows:

• Cavity diameter = 100 mm
• Cavity thickness = 10 mm
• Orifice diameter = 5 mm
• Orifice height = 5 mm

Three-component velocity data has been collected using the LDA system. These measurements were made at 16 streamwise locations on the central plane for the following three cases:

• Baseline without flow control (gzipped tar file)
• Low frequency case (VR=0.3, F+=0.2, f=40Hz) (gzipped tar file)
• High frequency case (VR=0.3, F+=0.6, f=120Hz) (gzipped tar file)

Description of the LDA data files (modified on July 21, 2020):

Note that all vertical components (V and v) were measured in the negative vertical direction (-Y). Therefore, all V and v components are negative of what they should be.

• h (mm) - Vertical distance from the surface of wall
• U (m/s) - axial velocity component (time-averaged) in the streamwise (X) direction
• V (m/s) - vertical velocity component (time-averaged) in the negative vertical (-Y) direction
• W (m/s) - horizontal (span-wise) velocity component (time-averaged) in the (Z) direction
• uu (m2/s2) - normal Reynolds stress in the streamwise direction
• vv (m2/s2) - normal Reynolds stress in the vertical direction
• ww (m2/s2) - normal Reynolds stress in the horizontal direction
• uv (m2/s2) - shear stress (time-averaged)
• uw (m2/s2) - shear stress (time-averaged)
• vw (m2/s2) - shear stress (time-averaged)

Return to: Data from Experiments - Intro Page

Recent significant updates:
07/21/2020 - corrected the description of the LDA data files
06/10/2020 - added link to corresponding LES data; also changed page title to match with LES page better

Privacy Act Statement

Accessibility Statement

Responsible NASA Official: Ethan Vogel
Page Curator: Clark Pederson
Last Updated: 11/04/2021