Turbulent flow and acoustic predictions over open cavity configurations at transonic speeds

Download

index.pdf

Date

2019

Author

Çoşkun, Seyfettin.

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

370
views

195
downloads

In modern military ﬁghters, internal carriage of weapons is vital in terms of high survivability, low observability and aerodynamic performance of the ﬁghter. During store release phases of operation, the aircraft will have to ﬂy with the cavity exposed to free stream conditions. When an aircraft internal weapons bay is exposed to free stream of air, a highly unsteady and complex ﬂow ﬁeld develops within the cavity. This triggers intense aero-acoustic environment in and around the cavity. Highly complex, unsteady and nonlinear ﬂow environment of a cavity may cause possible structural, acoustic and aerodynamic problems such as fatigue in structures, nose-up pitching moment on stores, resonance in cavity walls and etc. Therefore, it is desired to assure that internal stores, aircraft structures and internal weapon bay (IWB) structureandequipmentinsidetheIWBcanwithstandthisharshenvironmenttosuccessfully complete the mission under required conditions. In this respect, various cavity conﬁgurations such as clean cavity (i.e. no stores, no doors etc.), cavity with a generic store, cavity with doors and doors at different orientations are analyzed for the effects of each conﬁguration on cavity acoustic characteristics. Unsteady Reynolds-Averaged(URANS) and Detached Eddy Simulation (DES) turbulence model variants available in ANSYS/Fluent solver are utilized. It has been found out that although URANS models can predict the OASPL trends within the cavity with a level of accuracy, they are lack of accuracy in capturing the frequency spectra due to averaging nature of URANS models. On the other hand, IDDES model is quite successful in predicting both the noise intensity and the frequency spectra of various cavity conﬁgurations at transonic speeds.

Subject Keywords

Aeroacoustics., Keywords: Internal weapons bays, aeroacoustics, computational ﬂuid dynamics, cavity ﬂow

URI

http://etd.lib.metu.edu.tr/upload/12623283/index.pdf
https://hdl.handle.net/11511/43445

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

DYNAMIC MODELING AND CONTROL OF AN ELECTROMECHANICAL CONTROL ACTUATION SYSTEM Yerlikaya, Umit; Balkan, Raif Tuna (2017-10-13) Electromechanical actuators are widely used in miscellaneous applications in engineering such as aircrafts, missiles, etc. due to their momentary overdrive capability, long-term storability, and low quiescent power/low maintenance characteristics. This work focuses on electromechanical control actuation systems (CAS) that are composed of a brushless direct current motor, ball screw, and lever mechanism. In this type of CAS, nonlinearity and asymmetry occur due to the lever mechanism itself, saturation limit...
Flow and Noise Prediction of Doors-on M219 Cavity through Improved Delayed Detached Eddy Simulations Coşkun, Seyfettin; Özyörük, Yusuf (2019-05-14) High survivability and low observability requirements of modern fighter airplanes necessitate internal carriage of the stores. During their deployment the doors of internal weapon bays are opened transitionally, forming a cavity and hence a highly unsteady and nonlinear flow coupled with acoustic feedback mechanism. These processes present unsteady vibratory loads on the stores and structures. In the present paper, CFD computations of the doors-on M219 cavity with use of Improved Delayed Detached Eddy Simul...
ADJOINT-BASED AERODYNAMIC SHAPE OPTIMIZATION OF A STRAKE-DELTA WING CONFIGURATION Yutük, Kaan; Tuncer, İsmail Hakkı; Department of Aerospace Engineering (2021-11-8) Modern fighter aircraft compulsorily demand high maneuverability capability, which is mainly provided by an improved aerodynamic performance at high angles of attack. This is achieved by mostly employing strakes and canards. In this study, adjoint-based configuration and leading edge shape optimizations of a strake on a double-delta wing configuration are performed. SU2 is employed for flow and adjoint solutions. SU2 flow solutions are first verified on solutions for adaptive grids. In the configuration opt...
Aerodynamic design and performance analyses of grid fin in supersonic flow using design of experiments and computational fluid dynamics Dinçer, Erdem; Sezer Uzol, Nilay; Department of Aerospace Engineering (2022-2) Control surfaces are key components of missile aerodynamic performance that can create the necessary forces and moments to make maneuvers. Grid fins are unconventional control surfaces used for aerodynamic control of missiles. In this thesis, parametric design of grid fin is performed in terms of aerodynamic performance using Design of Experiments and Computational Fluid Dynamics. The 3-D, steady-state, compressible, viscous flow CFD simulations are performed for the complex grid fin geometries in supersoni...
Modelling and controller design of the gun and turret system for an aircraft Mert, Ahmet; Leblebicioğlu, Mehmet Kemal; Department of Electrical and Electronics Engineering (2009) Gun and gun turret systems are the primary units of the weapon systems of an aircraft. They are required to hit targets accurately during operations. That is why a complete, high precision control of weapon systems is required. This function is provided by accurate modeling of the system and the design of a suitable controller. This study presents the modeling of and controller design for the gun and turret system for an aircraft. For the controller design purpose, first the mathematical model of the system...

Citation Formats

S. Çoşkun, “Turbulent flow and acoustic predictions over open cavity configurations at transonic speeds,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Aerospace Engineering., Middle East Technical University, 2019.