Abstract
The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LPT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different Reynolds number cases have been investigated, namely Re = 200, 000 and Re = 70, 000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control — separated boundary layer interaction for the aforementioned Reynolds numbers.
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Abbreviations
- C f :
-
skin friction coefficient
- C p :
-
pressure coefficient \(= \frac{{p_{tin} - p}} {{p_{tin} - p_{in} }}\)
- C µ :
-
jet momentum coefficient
- f act :
-
actuator frequency
- L :
-
flat plate length
- L sep :
-
streamwise separation length
- p:
-
static pressure
- p t :
-
total pressure
- r :
-
jet to main flow velocity ratio \(= \frac{{U_{act} }} {{U_{in} }}\)
- R e :
-
isentropic inlet Reynolds number=U in L/ν
- St :
-
jet Strouhal number \(= \frac{{f_{act} L}} {{U_{in} }}\)
- T:
-
jet period
- Tu :
-
turbulence intensity
- u :
-
streamwise velocity
- U in :
-
Inlet streamwise velocity magnitude
- U act :
-
maximum outstroke velocity
- x :
-
streamwise coordinate
- x sep :
-
streamwise separation onset coordinate
- y :
-
normal to the wall coordinate
- ν:
-
kinematic viscosity
- ρ:
-
density
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Bernardini, C., Carnevale, M., Manna, M. et al. Turbine blade boundary layer separation suppression via synthetic jet: An experimental and numerical study. J. Therm. Sci. 21, 404–412 (2012). https://doi.org/10.1007/s11630-012-0561-2
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DOI: https://doi.org/10.1007/s11630-012-0561-2