Viscous simulation of F-16 like configuration at high AoA (original) (raw)

Aerodynamics of the F-15 At High Angle of Attack

53rd AIAA Aerospace Sciences Meeting, 2015

In this paper, the unstructured-grid flow solver, FUN3D, is used to compute the aerodynamic performance of F-15. A half model of F-15 with 14 million grid points is used for both steady and unsteady computations. The Detached Eddy Simulation (DES) method based on the Spalart-Allmaras (SA) turbulence model is used in the unsteady computation of the F-15 with high angle of attack. Computational results for the transonic steady cases of the F-15 vertical tail and the benchmark case of a cylinder in a cross flow are presented, showing excellent agreement with other numerical results and experimental measurements in the literature. Furthermore, unsteady pressure fluctuations on the F-15 vertical tail at a high angle of attack (22) are computed. The effect of the far field turbulence on the power spectrum of the pressure is studied, and the optimal turbulence level is determined to capture the dominant regime of the power spectrum of the pressure measured in wind tunnel tests. The FUN3D computation is thus expected to provide reliable pressure data for the prediction of the buffeting response of the F-15 vertical tail.

Lessons Learned from Numerical Simulations of the F-16XL Aircraft at Flight Conditions

Journal of Aircraft, 2009

Nine groups participating in the CAWAPI project have contributed steady and unsteady viscous simulations of a full-scale, semi-span model of the F-16XL aircraft. Three different categories of flight Reynolds/Mach number combinations were computed and compared with flight-test measurements for the purpose of code validation and improved understanding of the flight physics. Steady-state simulations are done with several turbulence models of different complexity with no topology information

CFD ANALYSIS OF F-16 FALCON

Development of a fast-moving aircraft with high lift coefficient and low drag coefficient is an essential requirement for the current scenario to support to modernize the military capability of any independent Nation. In this context, the aim of our project is to examine the Viscous, Compressible and Steady-state flow over the F-16 Fighting Falcon aircraft using computer modeling techniques and to compare the modeled results with the analytical results to emphasize the modernization and warble capability. This project outlines the development of a computational model of the F-16 Fighting Falcon model in a finite computational domain, segmentation of this domain into discrete intervals, application of the boundary condition such as Mach number or velocity and then obtaining the plots and results for the coefficient of pressure, lift coefficient, drag coefficient, etc.

High Resolution Turbulence Treatment of F/A-18 Tail Buffet

Journal of Aircraft, 2007

Unsteady tail loads of the F/A-18 are computed using various turbulence models at an angle of attack consistent with buffet induced by leading-edge extension vortex breakdown. Comparison of these industry standard turbulence models with the Detached Eddy Simulation (DES) hybrid RANS-LES approach reveals the inadequacies of RANS methods and the ability of DES to reproduce the observed unsteadiness at these conditions. Computed vortex breakdown position and frequencies of the DES method are shown to be accurate by comparison to flight test and experimental results. Finally, comparison of the DES unsteady tail pressures with flight-test tail pressures reveal the ability of the method to accurately reproduce F/A-18 tail buffet loads and is ready for inclusion in a fluid-structure interaction method.

Evaluation of Turbulence Modelling for the Incompressible Flow Simulations Around a Multi Delta Wing Configuration

HAL (Le Centre pour la Communication Scientifique Directe), 2021

In the present work, numerical simulations of the flow around a fighter aircraft at several angles of attack and two sideslip angles are performed with the flow solver ISIS-CFD which is an incompressible unsteady Reynolds-averaged Navier-Stokes method. Three RANS-based turbulence models, the isotropic k-ω SST, the non-linear anisotropic EARSM and the Reynolds stress transport model SSGLRR-ω and one hybrid RANS-LES model, the DDES-SST, are used. All these turbulence models are based on the k-ω model. Forces and moments as well as flow field data are compared with experimental measurements. For the RANS-based turbulence models, the results obtained with k-ω SST agree relatively well with the experimental data and it is the better approach for this class of turbulence models. However, the results obtained with DDES-SST are in better agreement with experiments.

Evaluation of Turbulence Models for the Prediction of Vortex Interaction Over a Fighter Aircraft

Le Centre pour la Communication Scientifique Directe - HAL - Diderot, 2020

In the present work, the numerical simulations of flow around a fighter aircraft at several angles of attack are performed with the flow solver ISIS-CFD which is an incompressible unsteady Reynoldsaveraged Navier-Stokes method. Three RANSbased turbulence models, as the isotropic k-SST, the non-linear anisotropic EARSM, and the Reynolds stress transport model SSGLRR- and one hybrid RANS-LES model, the DDES-SST, are used. All these turbulence models are based on k- model. Forces and moments as well as flow field data are compared with experimental measurements. For the RANS-based turbulence models, the results obtained with k- SST agree relatively well with the experimental data and it is the better approach for this class of turbulence models. However, the results obtained with DDES-SST are in better agreement with experiments.

Fluid Structure Interaction Simulation on the F/A-18 Vertical Tail

40th Fluid Dynamics Conference and Exhibit, 2010

Integrity Study (ASIP) to analyze the structural integrity of the entire airframe based on the Swiss design spectrum. To validate this study a full scale fatigue test was carried out at RUAG. By setting up the test facility and preparing the fatigue test loads using data from the

On the Effects of Turbulence Modeling and Grid Refinement on High-Lift Configuration Aerodynamic Simulations

Universidade de São Paulo, USP (ricardo.galdino@poli.usp.br) Instituto de Aeronáutica e Espaço, DCTA/IAE/ALA (joaoluiz.azevedo@gmail.com) Abstract The paper presents simulations over a trapezoidal wing with a single slotted flap and a slat. The calculations are performed for the high-lift con-figuration know as configuration one, which is characterized by slat and flap deflections of 30 and 25 , respectively. The simulations address both the actual configuration tested, with the sup-porting brackets for the high-lift devices, as well as a simplified configuration without the brack-ets. Both hybrid tetrahedral-prismatic and hexa-hedral meshes are considered in the calculations. For the purpose of analyzing the effect of the tur-bulence model, simulations are performed using the Spalart-Allmaras, Menter SST and cubic k turbulence models. The grids for the configura-tion without brackets range from 12 million to 22.8 million cells, whereas for the configuration with the brackets the gr...

Large-Eddy Simulation in the vicinity of the RAF-6E airfoil in a reduced domain

Large-eddy simulation using dynamic Smagorinsky Sub-Grid Scale model was performed to investigate the flow past an airfoil at an angle of attack of 5 • at chord Reynolds number of 122000. The simulations were carried out using the incompressible implicit secondorder finite volume method with a collocated variable arrangement implemented in ANSYS-FLUENT commercial code. Different computational grids were used both in terms of spanwise size and spanwise grid resolution to investigate its effect on the integral and instantaneous properties of the flow. The simulation scenarios were established in the aspect of the different smallest spanwise domain and finest grid shown the best results compare the measurements moreover 7 flow through number is enough to prepare comparison. Streamwise velocity components and velocity fluctuations of these numerical simulations were compared with Laser Doppler Anemometry measurements.