scholarly journals Theoretical and Experimental of Evaluation of Flow Field Over a Double Delta Wing at Supersonic Speeds

2019 ◽  
Vol 8 (2S11) ◽  
pp. 2939-2943

Numerical and experimental investigations of flay over double delta wing at supersonic speed are investigated . For numerical simulations , the body geometry is generated using SolidWorks software , mesh is created using Gambit and solution is obtained using Fluent sofivvare . For the experimental studies , stainless steel model is fabricated and tested in the supersonic Mind tunnel at Mach 2.5 at 0 and 5 angle of attack . The results are presented in the present paper

Author(s):  
S M Fraser ◽  
A M Abdel-Razek ◽  
M Z Abdullah

Three-dimensional turbulent flow in a model cyclone has been simulated using PHOENICS code and experimental studies carried out using a laser Doppler anemometry (LDA) system. The experimental results were used to validate the computed velocity distributions based on the standard and a modified k-∊ model. The standard k-∊ model was found to be unsatisfactory for the prediction of the flow field inside the cyclone chamber. By considering the strong swirling flow and the streamlined curvature, a k-∊ model, modified to take account of the Richardson number, provided better velocity distributions and better agreement with the experimental results.


2021 ◽  
Vol 49 (2) ◽  
pp. 395-400
Author(s):  
Manthan Patil ◽  
Rajesh Gawade ◽  
Shubham Potdar ◽  
Khushabu Nadaf ◽  
Sanoj Suresh ◽  
...  

Flow over a conventional delta wing has been studied experimentally at a subsonic flow of 20 m/sec and the flow field developed at higher angle of attack varying from 10° to 20° has been captured. A vortex generator is mounted on the leeward surface of the delta wing and its effect on the flow field is studied. The set of wing tip vortices generated over the delta wing is captured by the oil flow visualization and the streamline over the delta wing surface captured with and without a vortex generator are compared. Based on the qualitative results, the effect of the vortex generator on the lift coefficient is anticipated. Further, force measurement is carried out to quantitatively analyze the effect of vortex generator on the lift and drag coefficient experienced by the delta wing and justify the anticipation made out of the qualitative oil flow visualization tests. In the present study, the effect of mounting of a vortex generator is found to be minimal on the lift coefficient experienced by the delta wing. However, a significant reduction in the drag coefficient with increase in angle of attack was observed by mounting a typical vortex generator.


2021 ◽  
Vol 8 (8) ◽  
pp. 202275
Author(s):  
Liansong Peng ◽  
Mengzong Zheng ◽  
Tianyu Pan ◽  
Guanting Su ◽  
Qiushi Li

Dragonflies possess two pairs of wings and the interactions between forewing (FW) and hindwing (HW) play an important role in dragonfly flight. The effects of tandem-wing (TW) interactions on the aerodynamic performance of dragonfly hovering have been investigated. Numerical simulations of single-wing hovering without interactions and TW hovering with interactions are conducted and compared. It is found that the TW interactions reduce the lift coefficient of FW and HW by 7.36% and 20.25% and also decrease the aerodynamic power and efficiency. The above effects are mainly caused by the interaction between the vortex structures of the FW and the HW, which makes the pressure of the wing surface and the flow field near the wings change. During the observations of dragonfly flight, it is found that the phase difference ( γ ) is not fixed. To explore the influence of phase difference on aerodynamic performance, TW hovering with different phase differences is studied. The results show that at γ = 22.5°, dragonflies produce the maximum lift which is more than 20% of the body weight with high efficiency; at γ = 180°, dragonflies generate the same lift as the body weight.


2021 ◽  
Author(s):  
Peter P. Krimbalis

The development of Fibre Metal Laminates (FMLs) for application into aerospace structures represents a paradigm shift in airframe and material technology. By consolidating both monlithic metallic alloys and fibre reinforced composite layers, a new material structure is born exhibiting desired qualities emerging from its heterogeneous consituency. When mechanically fastened via pins, bolts and rivets, these laminated materials develop damage and ultimately fail via mechanisms that were not entirely understood and different than either their metallic or composite constituents. The development of a predictive methodology capable of characterizing how FMLs fastened with pins behave and fail would drastically reduce the amount of experimentation necessary for material qualification and be an invaluable design tool. The body of this thesis discusses the extension of the characteristic dimension approach to FMLS and the subsequent development of a new failure mechanism as part of a progressive damage infinte element (FE) modeling methodology with yielding, delamination and buckling representing the central tenets of the new mechanism. This yielding through delamination buckling (YDB) mechanism and progressive FE model were investigated through multiple experimental studies. The experimental investigations required the development of a protocol with emphasis on measuring deformation on a local scheme in addition to a global one. With the extended protocol employed, complete characterization of the material response was possbile and a new definition for yield in a pin bearing configuration was developed and subsequently extended to a tensile testing configuraiton. The performance of this yield definition was compared directly to existing definitions and was shown to be effective in both quasi-isotropic and orthotropic materials. The results of the experiments and FE simulations demonstrated that yielding (according to the new definition), buckling and delamination resulting in joint collapse and failure have all occurred within the stipulated predictions of the YDB mechanism.


2021 ◽  
Author(s):  
Peter P. Krimbalis

The development of Fibre Metal Laminates (FMLs) for application into aerospace structures represents a paradigm shift in airframe and material technology. By consolidating both monlithic metallic alloys and fibre reinforced composite layers, a new material structure is born exhibiting desired qualities emerging from its heterogeneous consituency. When mechanically fastened via pins, bolts and rivets, these laminated materials develop damage and ultimately fail via mechanisms that were not entirely understood and different than either their metallic or composite constituents. The development of a predictive methodology capable of characterizing how FMLs fastened with pins behave and fail would drastically reduce the amount of experimentation necessary for material qualification and be an invaluable design tool. The body of this thesis discusses the extension of the characteristic dimension approach to FMLS and the subsequent development of a new failure mechanism as part of a progressive damage infinte element (FE) modeling methodology with yielding, delamination and buckling representing the central tenets of the new mechanism. This yielding through delamination buckling (YDB) mechanism and progressive FE model were investigated through multiple experimental studies. The experimental investigations required the development of a protocol with emphasis on measuring deformation on a local scheme in addition to a global one. With the extended protocol employed, complete characterization of the material response was possbile and a new definition for yield in a pin bearing configuration was developed and subsequently extended to a tensile testing configuraiton. The performance of this yield definition was compared directly to existing definitions and was shown to be effective in both quasi-isotropic and orthotropic materials. The results of the experiments and FE simulations demonstrated that yielding (according to the new definition), buckling and delamination resulting in joint collapse and failure have all occurred within the stipulated predictions of the YDB mechanism.


1964 ◽  
Vol 68 (638) ◽  
pp. 106-110 ◽  
Author(s):  
J. K. Harvey

SummaryIn this paper an experiment is described in which a detailed study was made of the flow field associated with a slender sharp-edged delta wing which was rolling steadily at zero angle of attack to an air stream. The investigation was made by performing two pressure surveys: first , one of the static pressure acting on the wing’s surface and second by measuring the total-head distribution in the neighbourhood of the wing. From the former the local rolling-moment coefficients, Clp, are evaluated and these are compared with the predictions for attached flow, thus assessing the contributions to the forces acting on the wing which arise as a consequence of the leading-edge separations. The second set of surveys is used to construct a picture of the flow-field details and this is compared with that known to occur on a similar wing when it is set at an angle of attack to the airstream. One interesting finding is that the secondary separation which appears to cause the discrepancy between the theoretical predictions and the measurements made on slender wings at incidence, is absent in this configuration and thus it is concluded that these data could be used for a more meaningful test of the theory.


2016 ◽  
Vol 29 (5) ◽  
pp. 1196-1204 ◽  
Author(s):  
Mojtaba Dehghan Manshadi ◽  
Mehdi Eilbeigi ◽  
Mohammad Kazem Sobhani ◽  
Mehrdad Bazaz Zadeh ◽  
Mohammad Ali Vaziry

2014 ◽  
Vol 1044-1045 ◽  
pp. 654-658
Author(s):  
Wei Long ◽  
Zai Shuai Ling ◽  
Zhen Dang

The Steady flow simulation to selected the delta wing model for different angles of attack in the Maher number.The law of flow field changes with the angle of attack is gotten.Through the FLUENT simulation,The variation tendency of coefficient of lift and drag in the different angle of attack is gotten.Further reveals the change rule of Maher number, pressure, velocity and other parameters in the different angle of attack.With increasing angle of attack, Maher number distribution is sparse of the same position increases and the greater numerical.the distribution of velocity vector is sparse of the same position increases and the greater numerical.the pressure distribution is sparse of the same position increases and the greater numerical.


Author(s):  
Dmitri V. Alexandrov ◽  
Andrey Yu. Zubarev

This theme issue, in two parts, continues research studies of transport phenomena in complex media published in the first part (Alexandrov & Zubarev 2021 Phil. Trans. R. Soc. A 379 , 20200301. ( doi:10.1098/rsta.2020.0301 )). The issue is concerned with theoretical, numerical and experimental investigations of nonlinear transport phenomena in heterogeneous and metastable materials of different nature, including biological systems. The papers are devoted to the new effects arising in such systems (e.g. pattern and microstructure formation in materials, impacts of external processes on their properties and evolution and so on). State-of-the-art methods of numerical simulations, stochastic analysis, nonlinear physics and experimental studies are presented in the collection of issue papers. This article is part of the theme issue ‘Transport phenomena in complex systems (part 2)’.


Author(s):  
D. Sedlacek ◽  
S. Biechele ◽  
C. Breitsamter

AbstractFor an improvement of the flight stability characteristics of high-agility aircraft, the comprehension of the vortex development, behavior and break down is important. Therefore, numerical investigations on low aspect ratio, multiple-swept-wing configurations are performed in this study to analyze the influence of the numerical method on the vortex formation. The discussed configurations are based on a triple- and double-delta wing planform. Unsteady Reynolds-averaged Navier–Stokes (URANS) simulations and delayed detached eddy simulations (DDES) are performed for both configurations. The simulations are executed at Re $$= 3.0\times 10^6$$ = 3.0 × 10 6 , symmetric freestream conditions, and an angle of attack of $$\alpha = 16^\circ$$ α = 16 ∘ , for consistency with reference wind tunnel data. For the triple-delta-wing configuration, the results of the DDES show a satisfying accordance to the experiments compared to URANS, especially for the flow field and the pitching moment coefficient. For the double-delta-wing configuration, the URANS simulation provides reliable results with low deviation of the aerodynamic coefficients and high precision for the flow field development with respect to the experimental data.


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