Development of a Hybrid DSMC/Navier-Stokes Solver with Application to the STS-119 Boundary Layer Transition Flight Experiments

2011 ◽  
Author(s):  
K. Stephani ◽  
D. Goldstein ◽  
P. Varghese
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Transition ◽  
Navier Stokes ◽  
Layer Transition ◽  
Transition Flight

scholarly journals Aerothermodynamic Ground Tests in Support of the Boundary Layer Transition Flight Experiment

2020 ◽  
pp. 1-16
Author(s):  
Elizabeth F. Rieken ◽  
Scott A. Berry ◽  
Michelle L. Mason ◽  
Francis A. Greene
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Flight Experiment ◽  
Transition Flight

Numerical Investigation on the Second Stator Boundary Layer Under Clocking Effects: Comparison of v2f and LCL-Model

2008 ◽  
Author(s):  
Axel Heidecke ◽  
Bernd Stoffel
Keyword(s):  
Boundary Layer ◽  
Numerical Investigation ◽  
Separation Bubble ◽  
Measurement Data ◽  
Turbulence Models ◽  
Boundary Layer Transition ◽  
Navier Stokes ◽  
Layer Transition ◽  
Numerical Work ◽  
Boundary Layer Development

This paper presents the results of a numerical investigation of a 1.5-stage low pressure turbine. The main focus of the numerical work was the prediction of the stator-2 boundary layer development under the influence of the stator stator clocking. The turbine profile used for the examination is a so called high-lift-profile and was designed for a laminar-turbulent transition over a steady separation bubble. The boundary conditions were defined by the 1.5-stage test turbine located at our laboratory, where also the measurement data was derived from. The calculations were conducted with a two-dimensional Navier-Stokes solver using a finite volume discretisation scheme. The higher level turbulence models v′2-f and the LCL-turbulence model, which are capable to predict boundary layer transition were compared with measurement data at midspan.

Intermittency Based Unsteady Boundary Layer Transition Modeling: Implementation Into Navier-Stokes Equations

2005 ◽  
Author(s):  
M. T. Schobeiri
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Boundary Layer Transition ◽  
Wake Flow ◽  
Navier Stokes ◽  
Transition Model ◽  
Unsteady Boundary Layer ◽  
Layer Transition ◽  
Navier Stokes Equations ◽  
Unsteady Wake

This paper presents recent advances in boundary layer research that deal with an intermittency based unsteady boundary layer transition model and its implementation into the Reynolds averaged Navier-Stokes equations (RANS). RANS equations are conditioned to include the ensemble averaged unsteady intermittency function. The unsteady boundary layer transition model is based on a universal unsteady intermittency function developed earlier. It accounts for the effects of periodic unsteady wake flow on the boundary layer transition. The transition model is the result of an inductive approach analyzing the unsteady data obtained by experiments on a curved plate at zero-streamwise pressure gradient under periodic unsteady wake flow. To validate this model, systematic experimental investigations were conducted on the suction and pressure surfaces of turbine blades that were integrated into a turbine cascade test facility, which was designed for unsteady boundary layer investigations. This model is implemented into the above mentioned conditioned RANS-equations and calculation results are presented.

scholarly journals Compressible Direct Numerical Simulation of Low-Pressure Turbines—Part I: Methodology

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Richard D. Sandberg ◽  
Vittorio Michelassi ◽  
Richard Pichler ◽  
Liwei Chen ◽  
Roderick Johnstone
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Direct Numerical Simulation ◽  
Environmental Parameters ◽  
Boundary Layer Separation ◽  
Low Pressure ◽  
Boundary Layer Transition ◽  
Navier Stokes ◽  
Layer Transition ◽  
Background Turbulence

Modern low pressure turbines (LPT) feature high pressure ratios and moderate Mach and Reynolds numbers, increasing the possibility of laminar boundary-layer separation on the blades. Upstream disturbances including background turbulence and incoming wakes have a profound effect on the behavior of separation bubbles and the type/location of laminar-turbulent transition and therefore need to be considered in LPT design. Unsteady Reynolds-averaged Navier–Stokes (URANS) are often found inadequate to resolve the complex wake dynamics and impact of these environmental parameters on the boundary layers and may not drive the design to the best aerodynamic efficiency. LES can partly improve the accuracy, but has difficulties in predicting boundary layer transition and capturing the delay of laminar separation with varying inlet turbulence levels. Direct numerical simulation (DNS) is able to overcome these limitations but has to date been considered too computationally expensive. Here, a novel compressible DNS code is presented and validated, promising to make DNS practical for LPT studies. Also, the sensitivity of wake loss coefficient with respect to freestream turbulence levels below 1% is discussed.

The transient period for boundary layer disturbances

1999 ◽  
Vol 381 ◽  
pp. 89-119 ◽  
Author(s):  
D. G. LASSEIGNE ◽  
R. D. JOSLIN ◽  
T. L. JACKSON ◽  
W. O. CRIMINALE
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Temporal Evolution ◽  
Initial Conditions ◽  
Boundary Layer Transition ◽  
Navier Stokes ◽  
Spatial Evolution ◽  
Layer Transition ◽  
Transient Period ◽  
The Continuum

The onset of transition in a boundary layer is dependent on the initialization and interaction of disturbances in a laminar flow. Here, theory and full Navier–Stokes simulations focus on the transient period just after disturbances enter the boundary layer. The temporal evolution of disturbances within a boundary layer is investigated by examining a series of initial value problems. In each instance, the complete spectra (i.e. the discrete and the continuum) are included so that the solutions can be completely arbitrary. Both numerical and analytical solutions of the linearized Navier–Stokes equations subject to the arbitrary initial conditions are presented. The temporal evolution of disturbances during the transient period are compared with the spatial evolution of the same disturbances and a strong correlation between the two approaches is demonstrated indicating that the theory may be used for the transient period of disturbance evolution. The theory and simulations demonstrate that strong amplification of the disturbances can occur as a result of the inclusion of the continuum in the prediction of disturbance evolution. The results further show that any approach proposed for use in bypass boundary layer transition must include the transient growth that results from the continuum. Finally, although a connection between temporal and spatial evolution in the transient period has been demonstrated, a theoretical basis as an explanation for this connection remains the focus of additional study.

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