APPLICATION OF IMMERSED BOUNDARY METHOD ON INSTRUMENTED TURBINE BLADE WITH LES

2021 ◽  
pp. 1-11
Author(s):  
Bryn N Ubald ◽  
Rob Watson ◽  
Jiahuan Cui ◽  
Paul G. Tucker ◽  
Shahrokh Shahpar
Keyword(s):  
Immersed Boundary Method ◽  
Pressure Loss ◽  
Turbine Blades ◽  
Leading Edge ◽  
Immersed Boundary ◽  
Eddy Simulation ◽  
Boundary Method ◽  
Flow Features ◽  
Compressor And Turbine Blades ◽  
High Level

Abstract Leading edge instrumentation used in compressor and turbine blades for jet-engine test rigs can cause significant obstruction and lead to a marked increase in downstream pressure loss. Typical instrumentation used in such a scenario could be a Kiel shrouded probe with either a thermocouple or pitot-static tube for temperature/pressure measurement. High fidelity analysis of a coupled blade and probe requires the generation of a high-quality mesh which can take a significant amount of an engineer's time. The application of Immersed Boundary Method (IBM) and Large Eddy Simulation is shown in this paper to enable the use of an extremely simple mesh to observe the primary flow features generated due to the blade and probe interaction effects, as well as quantify downstream pressure loss to within a high level of accuracy. IBM is utilised to approximately model the probe, while fully resolving the blade itself through a series of LES simulations. This method has shown to be able to capture downstream loss profiles as well as integral quantities compared to both experiment and fully wall resolved LES without the need to spend a significant amount of time generating the ideal mesh. Additionally, it is also able to capture the turbulence anisotropy surrounding the probe and blade regions.

Application of Immersed Boundary Method on Instrumented Turbine Blade With LES

2020 ◽  
Author(s):  
Bryn N. Ubald ◽  
Rob Watson ◽  
Jiahuan Cui ◽  
Paul Tucker ◽  
Shahrokh Shahpar
Keyword(s):  
Immersed Boundary Method ◽  
Pressure Loss ◽  
Turbine Blades ◽  
Leading Edge ◽  
Immersed Boundary ◽  
Eddy Simulation ◽  
Boundary Method ◽  
Flow Features ◽  
Compressor And Turbine Blades ◽  
High Level

Abstract Leading edge instrumentation used in compressor and turbine blades for jet-engine test rigs can cause significant obstruction and lead to a marked increase in downstream pressure loss. Typical instrumentation used in such a scenario could be a Kiel-shrouded probe with either a thermocouple or pitot-static tube for temperature/pressure measurement. High fidelity analysis of a coupled blade and probe requires the generation of a high quality mesh which can take a significant amount of an engineers time. The application of Immersed Boundary Method (IBM) and Large Eddy Simulation is shown in this paper to enable the use of an extremely simple mesh to observe the primary flow features generated due to the blade and probe interaction effects, as well as quantify downstream pressure loss to within a high level of accuracy. IBM is utilised to approximately model the probe, while fully resolving the blade itself through a series of LES simulations. This method has shown to be able to capture downstream loss profiles as well as integral quantities compared to both experiment and fully wall-resolved LES without the need to spend a significant amount of time generating the ideal mesh. Additionally, it is also able to capture the turbulence anisotropy surrounding the probe and blade regions.

scholarly journals Comparative Studies of RANS Versus Large Eddy Simulation for Fan–Intake Interaction

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Yunfei Ma ◽  
Nagabhushana Rao Vadlamani ◽  
Jiahuan Cui ◽  
Paul Tucker
Keyword(s):  
Large Eddy Simulation ◽  
Turbulence Model ◽  
Immersed Boundary Method ◽  
Immersed Boundary ◽  
Flow Acceleration ◽  
Eddy Simulation ◽  
Boundary Method ◽  
Fan Effect ◽  
Wide Range ◽  
Large Eddy

The present research applied a mixed-fidelity approach to examine the fan–intake interaction. Flow separation induced by a distortion generator (DG) is either resolved using large eddy simulation (LES) or modeled using the standard k–ω model, Spalart–Allmaras (SA) model, etc. The immersed boundary method with smeared geometry (immersed boundary method with smeared geometry (IBMSG)) is employed to represent the effect of the fan and a wide range of test cases is studied by varying the (a) height of the DG and (b) proximity of the fan to the DG. Comparisons are drawn between the LES and the Reynolds-averaged Navier–Stokes (RANS) approaches with/without the fan effect. It is found that in the “absence of fan,” the discrepancies between RANS and LES are significant within the separation and reattachment region due to the well-known limitations of the standard RANS models. “With the fan installed,” the deviation between RANS and LES decreases substantially. It becomes minimal when the fan is closest to the DG. It implies that with an installed fan, the inaccuracies of the turbulence model are mitigated by the strong flow acceleration at the casing due to the fan. More precisely, the mass flow redistribution due to the fan has a dominant primary effect on the final predictions and the effect of turbulence model becomes secondary, thereby suggesting that high fidelity eddy resolving simulations provide marginal improvements to the accuracy for the installed cases, particularly for the short intake–fan strategies with fan getting closer to intake lip.

NUMERICAL ANALYSIS OF BULK DRAG COEFFICIENT IN DENSE VEGETATION BY IMMERSED BOUNDARY METHOD

2011 ◽  
Vol 1 (32) ◽  
pp. 48 ◽  
Author(s):  
Tomohiro Suzuki ◽  
Taro Arikawa
Keyword(s):  
Drag Coefficient ◽  
Immersed Boundary Method ◽  
Three Dimensional ◽  
Vertical Cylinder ◽  
Immersed Boundary ◽  
Dense Vegetation ◽  
Eddy Simulation ◽  
Boundary Method ◽  
Large Eddy ◽  
Good Agreement

In this paper, bulk drag coefficient in rigid dense vegetation is investigated mainly by using a three dimensional numerical simulation model CADMAS-SURF/3D by incorporating Immersed Boundary Method to calculate flow around the vertical cylinder in the Cartesian grid. Large Eddy Simulation is also incorporated as a turbulence model. Firstly, validation of the developed model is conducted with a single cylinder in the flow field based on literature. All the results obtained here (Re=300, 3,900 and 8,000) show good agreement with the reference data in literature. After the validation, multiple cylinders are allotted in three different densities (S/D=2.8, 2.0, 1.4) in a numerical wave tank and numerical simulations are conducted to investigate bulk drag coefficient. The result shows that the ratio of bulk drag coefficient to drag coefficient, which represents a reduction, is not just a function of density but a function of parameter 2a/S, in which 2a is stroke of the motion and S is cylinder distance. 2a is less than S, the effect of the density is neglected because the wake does not reach the other cylinders even when the density is high. On the contrary, it might affect the ratio of bulk drag coefficient to drag coefficient when the stroke of the motion is larger than the cylinder distance even when the density is low. In general, the ratio of bulk drag coefficient to drag coefficient decreases when 2a/S increases.

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