An Examination of Key Aerodynamic Modeling Issues Raised by the NREL Blind Comparison

2002 ◽  
Author(s):  
Frank N. Coton ◽  
Tongguang Wang ◽  
Roderick A. McD. Galbraith
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Unsteady Aerodynamics ◽  
Measured Data ◽  
Data Set ◽  
Aerodynamic Modeling ◽  
Blade Section ◽  
Wake Model ◽  
Blind Comparison ◽  
Specific Modeling

This paper describes some recent work undertaken in the aftermath of the ‘blind comparison’ with the NREL Unsteady Aerodynamics Experimental data collected in the NASA Ames wind tunnel. The data set collected in the NASA Ames tunnel represents a unique opportunity for aerodynamic modelers to enhance the capability of prediction schemes by comparison with ‘clean’ aerodynamic data. In this paper, the sensitivity of the results predicted by the Glasgow University prescribed wake model (HAWTDAWG) to a range of parameters including the blade section aerodynamic data is examined with reference to the measured data. In addition, specific modeling considerations highlighted by the measured data set are also discussed.

Joint Computational/Experimental Aerodynamic Study of a Simplified Tractor/Trailer Geometry

2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Subrahmanya P. Veluri ◽  
Christopher J. Roy ◽  
Anwar Ahmed ◽  
Rifki Rifki ◽  
John C. Worley ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Test Section ◽  
Bluff Body ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Initial Assessment ◽  
Validation Data ◽  
Data Set ◽  
Fine Mesh

Steady-state Reynolds averaged Navier–Stokes (RANS) simulations are presented for the three-dimensional flow over a generic tractor trailer placed in the Auburn University 3×4 ft2 suction wind tunnel. The width of the truck geometry is 10 in., and the height and length of the trailer are 1.392 and 3.4 times the width, respectively. The computational model of the wind tunnel is validated by comparing the numerical results with the data from the empty wind tunnel experiments. The comparisons include the boundary layer properties at three different locations on the floor of the test section and the flow angularity at the beginning of the test section. Three grid levels are used for the simulation of the truck geometry placed in the test section of the wind tunnel. The coarse mesh consists of 3.4×106 cells, the medium mesh consists of 11.2×106 cells and the fine mesh consists of 25.8×106 cells. The turbulence models used for both the empty tunnel simulations and the truck geometry placed in the wind tunnel are the standard Wilcox 1998 k-ω model, the SST k-ω model, the standard k-ε model, and the Spalart–Allmaras model. The surface pressure distributions on the truck geometry and the overall drag are predicted from the simulations and compared with the experimental data. The computational predictions compared well with the experimental data. This study contributes a new validation data set and computations for high Reynolds number bluff-body flows. The validation data set can be used for initial assessment in evaluating RANS models, which will be used for studying the drag or drag trends predicted by the baseline truck geometries.

scholarly journals Implementation of the BEM skewed-wake model within the multibody aero-elastic solver Cp-Lambda

2020 ◽  
Vol 173 ◽  
pp. 02004
Author(s):  
Igor Petrović ◽  
Filippo Campagnolo ◽  
Tadej Kosel ◽  
Carlo L. Bottasso
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Flow Conditions ◽  
Aerodynamic Loads ◽  
Model Predictions ◽  
Wind Tunnel Data ◽  
Wake Model ◽  
Nrel Phase Vi ◽  
Local Variability

To account for the problem of an azimuthally constant induction in the BEM method, which influences on incorrectly predicted aerodynamic loads in the yawed flow, a skewed-wake model implementation to the BEM method has been performed. The numerical aerodynamic loads have been compared with the wind tunnel data of the NREL Phase VI and against another numerical campaign. At first, the model predictions have been validated against experimental data performed with aligned flow conditions, showing a reasonable match. Successively, the model predictions are validated against experimental results obtained with the wind turbine yawed. Results show, a possible better prediction of loads at yawed flow with Skewed-Wake correction, however the method does not overall correlate better, compared to the BEM method with implemented local variability of the induction factor.

EXPERIMENTAL DATA SET NO. 24: PHASE DISTRIBUTION IN BUBBLY FLOW

1992 ◽  
Vol 6 (1-4) ◽  
pp. 257-301 ◽  
Author(s):  
Akimi Serizawa ◽  
Isao Kataoka ◽  
Itaru Michiyoshi
Keyword(s):  
Experimental Data ◽  
Phase Distribution ◽  
Bubbly Flow ◽  
Data Set

Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

2009 ◽  
Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Axial Flow ◽  
Experimental Results ◽  
Scale Model ◽  
Data Set ◽  
Pressure Profiles ◽  
Scale Models ◽  
Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

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