Stability and Sensitivity Analysis of a Low-speed Jet in Cross-flow

2019 ◽  
Author(s):  
Marc A. Regan ◽  
Krishnan Mahesh
Keyword(s):  
Sensitivity Analysis ◽  
Cross Flow ◽  
Low Speed ◽  
Jet In Cross Flow

Adjoint sensitivity and optimal perturbations of the low-speed jet in cross-flow

2019 ◽  
Vol 877 ◽  
pp. 330-372
Author(s):  
Marc A. Regan ◽  
Krishnan Mahesh
Keyword(s):  
Shear Layer ◽  
Time Horizon ◽  
Cross Flow ◽  
Adjoint Equations ◽  
Low Speed ◽  
Time Horizons ◽  
Jet In Cross Flow ◽  
Jet Nozzle ◽  
The Cross ◽  
Short Time

The tri-global stability and sensitivity of the low-speed jet in cross-flow are studied using the adjoint equations and finite-time horizon optimal disturbance analysis at Reynolds number $Re=2000$, based on the average velocity at the jet exit, the jet nozzle exit diameter and the kinematic viscosity of the jet, for two jet-to-cross-flow velocity ratios $R=2$ and $4$. A novel capability is developed on unstructured grids and parallel platforms for this purpose. Asymmetric modes are more important to the overall dynamics at $R=4$, suggesting increased sensitivity to experimental asymmetries at higher $R$. Low-frequency modes show a connection to wake vortices. Adjoint modes show that the upstream shear layer is most sensitive to perturbations along the upstream side of the jet nozzle. Lower frequency downstream modes are sensitive in the cross-flow boundary layer. For $R=2$, optimal analysis reveals that for short time horizons, asymmetric perturbations dominate and grow along the counter-rotating vortex pair observed in the cross-section. However, as the time horizon increases, large transient growth is observed along the upstream shear layer. When $R=4$, the optimal perturbations for short time scales grow along the downstream shear layer. For long time horizons, they become hybrid modes that grow along both the upstream and downstream shear layers.

scholarly journals Low Speed Wind Tunnel Flow Diagnostics and Benchmark Cases for Thermal Fluids CFD Validation Efforts

2020 ◽  
Author(s):  
Paul Kristo ◽  
Saniya Sohail ◽  
Ryan S. Read ◽  
Mark L. Kimber
Keyword(s):  
Wind Tunnel ◽  
Cross Sections ◽  
Cross Flow ◽  
Reynolds Stresses ◽  
Cfd Validation ◽  
University Of Pittsburgh ◽  
Low Speed ◽  
Thermal Fluids ◽  
Jet In Cross Flow ◽  
Flow Past A Cylinder

A low speed, closed loop wind tunnel at Texas A&M University is presented for the study of turbulent mixing produced by a variety of flows types. Anticipated experiments range from canonical “unit flows” to more complex combinations of flows and geometries. Originally located at the University of Pittsburgh, the facility has since been re-located to the Thermal Hydraulics Verification and Validation (THVV) laboratory at Texas A&M University. The tunnel has undergone considerable modification and updated diagnostics prompting renewed interest in flow quality assessment. This includes a thorough mapping of the tunnel inlet velocity profile provided by Particle Image Velocimetry (PIV) measurements. Additional temperature and gage pressure measurements complete the assessment of system capabilities. These preliminary diagnostics yield empirically determined boundary conditions and fluid property correlations necessary for Computational Fluid Dynamics (CFD) model validation. The article concludes with the presentation of two unit flow types, including flow past a cylinder, with three distinct cross sections, and a single round jet in cross flow at three velocity ratios. The unit flows serve as initial benchmarks for THVV simulation efforts. Key validation metrics are presented for each benchmark including ensemble averaged velocities, Reynolds stresses, and proper orthogonal decomposition (POD) eigenvectors.

Large Eddy Simulation of a Supercritical Fuel Jet in Cross Flow using GPU-Acceleration

2016 ◽  
Author(s):  
Kalyana C. Gottiparthi ◽  
Ramanan Sankaran ◽  
Anthony M. Ruiz ◽  
Guilhem Lacaze ◽  
Joseph C. Oefelein
Keyword(s):  
Large Eddy Simulation ◽  
Cross Flow ◽  
Gpu Acceleration ◽  
Eddy Simulation ◽  
Jet In Cross Flow ◽  
Fuel Jet ◽  
Large Eddy

Flow structure of the plane turbulent impinging jet in cross flow

2001 ◽  
Vol 39 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Meilan Qi ◽  
Zhicong Chen ◽  
Renshou Fu
Keyword(s):  
Flow Structure ◽  
Cross Flow ◽  
Impinging Jet ◽  
Jet In Cross Flow

A Visual Study of a Round Jet in Cross-Flow

1992 ◽  
pp. 173-177
Author(s):  
R. M. Kelso ◽  
T. T. Lim ◽  
A. E. Perry
Keyword(s):  
Cross Flow ◽  
Round Jet ◽  
Visual Study ◽  
Jet In Cross Flow
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