International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 1, January 2018, pp. 538–548, Article ID: IJMET_09_01_058 Available online at http://iaeme.com/Home/issue/IJMET?Volume=9&Issue=1 ISSN Print: 0976-6340 and ISSN Online: 0976-6359

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ANALYTICAL INVESTIGATION OF IMPLEMENTATION OF FENCES ON CROPPED DELTA FOR THE IMPROVEMENT OF PERFORMANCE PARAMETERS

Arun. M. P and Dr. M. Satheesh Research Scholar and Assistant Professor, Department of Mechanical Engineering, Noorul Islam Centre for Higher Education, Tamilnadu, India

ABSTRACT In the present work providing, better performance characteristics of delta at subsonic speeds without interference to its supersonic flight characteristics. The delta configuration has low aspect ratio, this raises the critical Mach number and the planform tends to reduce the tip-stalling. Delta planform is stronger than a similar and the additional advantages are simplicity of manufacture, strength, and substantial interior volume for fuel and other equipment. In this paper an aerodynamic of the delta wing at different angle of attacks has been done followed by computational method. Key words: Delta Wing, Lift and Drag Coefficient, Pressure Coefficient, . Cite this Article: Arun. M. P and Dr. M. Satheesh, Analytical Investigation of Implementation of Fences On Cropped Delta Wing For The Improvement of Performance Parameters, International Journal of Mechanical Engineering and Technology 9(1), 2018. pp. 538–548. http://iaeme.com/Home/issue/IJMET?Volume=9&Issue=1

1. INTRODUCTION In the modern era of aircrafts, the worldwide trying to develop a new tactic fighters and bombers in large scale. Producing and maintaining several fleet of each one with different purpose, consumes a lot of money and man power. After precise and critical analysis of the cropped delta, it is found out that the wing will at an angle of 180. Here the main aim is to increase the stall angle and also to produce better lift. Hence the simple delta needs to be incorporated with aerodynamic changes that are to produce better performance at low speeds, simultaneously keeping in mind how the delta will perform at supersonic speed, because for the same purpose the structural changes in the wing i.e. increase in the area was not inherited and aerodynamic changes are promoted.

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The challenge is to design a method which will produce the right amount of lift and at the same time do not produce problems when the aircraft is at its high speed regime, then it is concluded that the wing fence design will be apt. Though the wing fence is an older concept but its usage in a delta planform as used in the following configuration is new and it needs to be analyzed deeply. [1][6] This deals with a structural and aerodynamic design modifications that can be made to the delta so that can operate at high as well as low speed. The change in aerodynamic design affects the structure. Through this research the changes in the behavior of conventional delta wing and modified delta wing are going to analysis with the help of different CAD CAE application software’s. The journal titled “Calculation of Derivatives for a Cropped Delta Wing with Subsonic Leading Edges Oscillating in a Supersonic Air Stream.”[3] By J. Watson published in the year 1958 was referred and the lift, pitching moment and full-span constant-chord control hinge- moment are derived for a cropped delta wing describing harmonic plunging and pitching oscillations of small amplitude and low-frequency parameter in a supersonic air stream was studied. In 2001, A A PASHILKAR published his journal titled “Surface pressure model for simple delta at high angles of attack [8].” From which Delta wing surface pressure aerodynamic modeling high angle of attack could be studied. “Leading-Edge Vortex Structure of Non-slender Delta Wings at Low Reynolds Number” [7] published by Michael V. & Morteza Gharib in 2003 stated that Upstream progression of vortex breakdown with increasing angle of attack exhibited extensive regions of stream wise undulation. Leading- edge shear-layer roll up was also observed. The aerodynamic and the vertical flow structure over simple delta wings undergoing either a pitching or rolling motion. Experimental information on the flow structure over delta wings and complete aircraft configurations could be studied from “The unsteady aerodynamics of slender wings and aircraft undergoing large amplitude maneuvers [9].” By Robert C. Nelson & Alain Pelletier in 2003. In the “Fluid Structural Interaction of Unsteady Aerodynamics” [15] by Z.M. Fairuz, M.Z Abdulla, H Yousuff and M.K Abdullah in 2013; they clearly state about the aerodynamic force acting on the surface of the wing and the inertial force due to acceleration or deceleration of wing’s mass. Karna S. Patel et al. [16] detailed the CFD hit or miss of the hover from a well-known end to the other NACA 0012 airfoil and finish that at the no one degree of trawl of clash there is no grow long arm of the law generated. The rival of charge police and worth of charge coefficient besides increased for all that the meet of increment in oblige force and brought pressure to bear up on coefficient is quite ebb compare to surge force. In this design, NACA 2412 airfoil [17] is secondhand to diamond in the rough the handle, everywhere the alternately digit is the ceiling camber in hundredths of the chord, the instant digit is the motion picture studio of the maximum body from the head edge in tenths of the chord, and the eke out an existence two digits delineate the maximum cross measure in hundredths of the chord [18]. The parameters are preferred, one as airfoil chord c = 0.3m, airfoil two some l = 1.6m. These dimensions are second-hand to boast the concealed rod ideal, which are also stable mutually the unmask disclosure of a zip code of explain UAVs samples in Vietnam. Lift and brought pressure to bear up on forces were defined right to fluid-structure interaction [19]. The force components that which conform the velocity inlet are collected. From these data, two graphs of the relationship surrounded by climb, brought pressure to bear up on versus reliant velocity between the wing and the airflow are unprotected.

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The standard course in evaluating the rocket and oblige coefficients from an Euler CFD sequence is to entire the charge on the gat to one foot [20]. This means does not what one is in to for attentive the brought pressure to bear up on coefficients (all for all that one brought pressure to bear up on value was negative). This indiscretion occurs seeing the airplane lift is represented by triangles; therefore valuable grid idea intend be second-hand in censure to in a satisfactory manner decide curved surfaces [21]. Also, errors are instructed from the subtraction of two rich forces in the stray direction. Therefore, the oblige distribution am about to be accurately known in censure to confirm the oblige force [22]. These two problems represent that in sending up the river for a lift amalgamation plan of attack to be ironclad, an ace computational grid intend be second-hand, resulting in daydream run times. Another problem with rocket integration course is that they became associated with different urge components into one resultant urge coefficient. It is pertinent, by way of explanation in conceptual study, to recognize how the move is considering produced so the aircraft gave a pink slip be efficiently designed [22].These limitations of the rocket integration technique have influenced researchers to catch a glimpse of at disparate methods to consider the surge and charge coefficients generated by CFD. One manner is the Wake Integration technique. In this approach, the brought pressure to bear up on is computed from the worldly the eighth wonder of the world that causes charge forces [22]. This is done by evaluating the vortex and entropy produced on a plane seesaw to the flow which lies downstream from the aircraft [21]. The vortices produced are results of the lift induced urge, and the entropy concept is on top of each other to the wave urge [23]. Thus, this manner will be second-hand in this analysis as a result of it is not as bilateral on the grid resolution as surface integration, and it separates the move components by the physical phenomena that construct the drag. These collections are taken from the literature survey and implement to this research. If from times to times the civil aeronautics industry conceives projects that change the way passengers fly, whether it is shorting distances, increasing comfort or decreasing prices, a parameter which has been a constant barrier, in the commercial or executive sector, is the limited speed of subsonic and transonic flights. This study has for an aim the creation of a preliminary design of the primary structure of an aircraft wing all made of composite and comparison to the same design in aluminum.

2. DESIGNING OF PROPOSED MODELS The delta design is one of the major discoveries in the history of aeronautics. It was revolutionized with the Convair 102 and was a major consideration during the cold war era, but in the late seventies and eighties the delta wing lost its charm. The delta wing aircrafts were very unstable so that the manual controlling was very difficult at high speeds. Later in 90s by the computerized controlling over manual and fly by wire technologies made a way for the delta wing to prove its worthiness again. The project concentrates on designing a wing plan form in simple nature and functionally effective. After pondering light on many conventional deltas like the Mig-21, XF-Convair, the Mirages, the Mirage III, and the Eurofighter Typhoon, is found apt as the reference for designing the wing [9]. The Eurofighter Typhoon is a very successful design at high speeds but it is unstable at low speeds, hence it is unsuitable for ground attack roles, also the taking off and landing is done at high speeds because of the delta configuration. Hence it needs revival in its low speed characteristics.

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2.1. Cropped Delta Wing Here an attempt is made to improve general lift characteristics of a cropped delta wing which is very similar to that of a Eurofighter Typhoon[10] but it has to be kept in mind that the air foil used in the same is confidential and was substituted with MH60[11] Air foil. Also the Mach number used for analysis is 0.3 Mach. This is the speed at which the true low speed characteristics of a wing are tested. Design of the delta wing is done using CATIA V5R21 software. Choosing the dimensions were carried out based on a trial and error method, where in different parameters of each aircraft is pitched against each other and subsequently the apt design is selected. The model is then analyzed at different angle of attacks to find out the stall angle and based on the findings an improvement technique will be developed. The specification of the wing designed as follows: From the gathered data the following calculations are performed to obtain root and tip chord. Ct/Cr = 0.0635 (1) Let Ct = x; Cr = x/0.0635 For each term of Eq. (1) the following expressions are formulated: S = 2[(Ct * b/2) + (b/2 * (Cr - Ct) * 0.5)] (2) Substituting the values in the above equation and solving we get S = 2[(Ct * b/2) + (b/2 * (Cr - Ct) * 0.5)] 50.51 = 2[(x * 5.475) + (5.475 * (0.0635 *x - x) * 0.5)] X = 0.551 So Ct = X = 0.551m (3) Cr = 0.551/0.0635 = 8.67m (4) Table 1 Specifications of Cropped delta wing with their parameters

Table 1 Specifications of Cropped delta wing Parameters Specifications Wing span 10.95m (35ft 11in) Gross area 50.0m2 (538ft2). Aspect ratio 2:205 Root chord 8.67m Tip chord 0.551m Sweep angle 67.280 The Air foil geometry is exported as dxf file such that it could be associated with any CAD software. Here the dxf file is being imported into CATIA. Using the appropriate tools in the CAD software, a 3D model of delta wing has been created.

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Figure 1 3D Diagram of Cropped Delta Wing in CATIA

2.2. Cropped Delta Wing with Fence The challenge is to design a method which will produce the right amount of lift and at the same time do not produce problems when the aircraft is at its high speed regime, then it is concluded that the wing fence design will be apt. Though the wing fence is an older concept but its usage in a delta planform as used in the following configuration is new and it needs to be analyzed deeply [1][6]. A 50% of main chord length of the air foil is a good length of the fence. The length more than that will not produce any increased effect. The root chord airfoil geometry of 8475mm in length was trimmed at 3199mm from and 1286mm leaving a length of 3990mm almost a 45% of the root chord. The fence will have 10 mm of maximum thickness and 300mm of maximum height. Here the wing fence is placed on the same wing which is created prior to this and the wing fence is placed in such a location that it is somewhere in the middle that not in the . The software CATIA V5R21 is used for the construction of the fence, prior to that the airfoil selection is very critical, hence the software JAVAFOIL is used to understand the various features of the airfoil MH60. The fences are placed at 1/3 of wing span from the tip on each side.

Figure 2 Cropped Delta Wing with Fence in CATIA

http://iaeme.com/Home/journal/IJMET 542 [email protected] Analytical Investigation of Implementation of Fences On Cropped Delta Wing For The Improvement of Performance Parameters 3. COMPUTATIONAL ANALYSIS The cropped delta wing is then exported to ANSYS FLUENT V14.0 software and analyzed by setting the boundary conditions like Mach number of the flow over wing and the angle of attack.

3.1 Cropped Delta Wing The Key parameters selected for the analysis are as follows: Velocity/Mach no - 100m/s/0.3* Angle of Attack -120 - +190 Increment in angle of attack by - 30 Turbulence model used - K-omega model Static pressure (P) is the component of pressure force which acts normal to the wing. The variation is shown with different color schemes as indicated by the diagram. The yellow shade shows higher static pressure regions and cyan shades show the lower static pressure regions. The static pressure varies from about 3.08×102 Pa at the leading to -7.74×102 Pa at the trailing edge.

Figure 3 Static Pressure Distributions over Cropped Delta Wing The wing dynamic pressure analysis is conducted here a high pressure area is developed on the leading edge. It has a value of 6.59×103 Pa and the area inside has a dynamic pressure of 7.06×103 Pa as maximum. Hence over that region a uniform pressure distribution is obtained.

Figure 4 Dynamic Pressure Distributions over Cropped Delta Wing

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The free stream velocity of air is taken as 0.3 Mach and delta wing with an aspect ratio of 2.205 generates a CL value of 1.448. The coefficient of lift varies with the variation in free stream velocity and angle of attack. Here the flow velocity is 0.3 Mach which in turn 0 produces CL value of 2.835393at angle of attack 9 . The following table gives the CL & CD values at different angle of attacks. The coefficient of drag should be minimized to the least as much as possible in order to achieve maximum aerodynamic efficiency. The total drag is the sum of induced and the parasite drags as in the drag polar equation. Table 2 Relationship between Angle of attack, coefficient of lift and drag of cropped delta wing without fence

Table 2 CL Vs. angle of attack (α in degree) & CDVs angle of attack (α in degree) Without Fence Without Fence Angle of Attack Coefficient Of Coefficient Of Lift Drag -10 0.39202491 -0.14445411 -9 0.39199652 0.014923978 -6 0.39092594 0.49430373 -3 0.38824211 0.97275338 0 0.38383498 1.4483303 3 0.37767297 1.9186529 6 0.36997274 2.3760617 9 0.36030673 2.835393 12 0.34949739 3.2857187 15 0.33847312 3.7180452 18 0.32688101 4.014101 3.2 Cropped Delta Wing with Fence The Navier-Stokes equations are the basic governing equations for a viscous, heat conducting fluid. It is a vector equation obtained by applying Newton's Law of Motion to a fluid element and is also called the momentum equation. The free stream velocity is 0.3 Mach. The static pressure variation is shown with different color schemes as indicated by the diagram. The yellow shade shows higher static pressure regions and cyan shades show the lower static pressure regions. The static pressure varies from about 8.14×102 Pa at the leading to 3.1×102 Pa in the area surrounding the wing fence.

Figure 5 Static Pressure Distributions over Cropped Delta Wing with Fence

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The wing dynamic pressure analysis is conducted here a high pressure area is developed on the leading edge. It has a value of 7.26×104 and the area surrounding the wing fence region has a dynamic pressure of 6.07×103. Hence over that region a uniform pressure distribution is obtained.

Figure 6 Dynamic Pressure Distributions over Cropped Delta Wing with Fence

The following table gives the CL & CD values at different angle of attacks of cropped delta wing with fence. Table 2 Relationship between Angle of attack, coefficient of lift and drag of cropped delta wing with fence

Table 2 CL Vs. angle of attack (α in degree) & CDVs angle of attack (α in degree) With Fence With Fence Angle of Attack Coefficient Of Coefficient Of Lift Drag -11.67 -0.00507 0.428578 -11.66 0.000164 0.428625 -10 0.23454 0.43031 -9 0.375619 0.431109 -6 0.803226 0.432376 -3 1.219399 0.431964 0 1.637118 0.429677 3 2.058281 0.425097 6 2.540528 0.419844 9 2.9741 0.412375 12 3.4103 0.403366 15 3.874192 0.393147 18 4.145454 0.381904 19 4.238791 0.378026 19.535 4.300624 0.375838

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4. RESULTS AND DISCUSSIONS o In the case of cropped delta wing generation of lift starts at -9.1 . It possesses a positive CL at o o that angle of attack. The CL gradually increases from this angle of attack up to 18 . After 18 of angle of attack, it starts to reduce the Lift, called Stalling. The CD gradually decreases from -9.1o angle then tends to increase at 18o. In the effect of fence, generation of lift starts at - o 11.66 . It indicates a positive CL at that angle of attack. The CL gradually increases from this o o angle of attack up to 19.535 . After 19.535 of angle of attack, it starts to Stall. The CD gradually increases from -11.6o angle to 0o angle and then tends to decrease up to 19.535o.Again it increases from the stalling angle. Plotting graphically the values in the table we obtain the following graphs.

CL VS. Angle of Attack 5 4.5 4 3.5 3 2.5 L C 2 1.5 1 0.5 0 -15 -10 -5 -0.5 0 5 10 15 20 25 Angle of Attack

without fence with fence

Figure 7 Comparison of CL and angle of attack of cropped delta wing with fence and without fence

CD VS. Angle of Attack 0.5 0.45 0.4 0.35 0.3

D 0.25 C 0.2 0.15 0.1 0.05 0 -15 -10 -5 0 5 10 15 20 25 Angle of Attack

without fence with fence

Figure 8 Comparison of CD and angle of attack of cropped delta wing with fence and without fence

http://iaeme.com/Home/journal/IJMET 546 [email protected] Analytical Investigation of Implementation of Fences On Cropped Delta Wing For The Improvement of Performance Parameters 5. CONCLUSION This present work has successfully validated the increased effectiveness of delta wing by the use of wing fences. Through the CFD environment the CL, C D and the angle of attack values for delta wing with and without wing fences were generated and a comparative study was conducted. This unrevealed the increased lift characteristics of the delta wing with fences. The average increase in CL is 13.03% with a small increment CD in say 9%. The stall angle has increased by 1.535o.

REFERENCES

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[19] Jin Y., Yuan X., Shin B.R., Numerical Analysis of the Airfoil’s Fluid-Structure Interaction Problems at Large at Large Mean Incidence Angle, Proc. ICCFD, Sydney, Australia, 15–19 July 2002. [20] Chao, D. D., and van Dam, C. P., Airfoil Prediction and Decomposition, AIAA Paper 98- 2783. [21] Giles, Michael B. and Cummings, Russell M., Wake Integration for Three- Dimensional Computations: Theoretical Developments, Journal of Aircraft, Vol. 36, No. 2, 1996, pp. 357-365. [22] van Dam, C. P., Nikfetrat, K., Wong, K., and Vijgen, P. M. H. W., Drag Prediction at Subsonic and Transonic Speeds Using Euler Methods, Journal of Aircraft, Vol. 32, No. 4, pp. 839-845. [23] Hunt, David L., Cummings, Russell M. and Giles, MichaelB., Determination of Drag from Three-Dimensional Viscous and In viscid Flowfield Computations, AIAA Paper 97- 2257, June 1997 [24] John David Anderson (Jr) (1985) Fundamentals of Aerodynamics Tata McGraw-Hill Education, ISBN: 0070700125, 9780070700123 [25] Bungartz, Hans-Joachim; Schäfer, Michael, eds. (2006).’Fluid-structure Interaction: Modelling, Simulation, Optimization’ Springer-Verlag. ISBN 3540-34595-7. [26] Stefan Wiggen, German Aereospace Center (DLR), Institute of Aeroelasticity, Bunsenstrasse 10, 37073 Göttingen, Germany-‘Unsteady pressure distributions at the wind tunnel model of a pitching Lambda wing with development of vortical flow’.12 October 2015-Elsevier [27] Yunpeng Qin, Peiqing Liu, Qiulin Qu, Hao Guo, Beijing University of Aeronautics and Astronautics, Beijing, 100191, China- [28] Numerical study of aerodynamic forces and flow physics of a delta wing in dynamic ground effect-6 February 2015-Elsevier [29] G.J. Van Wylen and R.E. Sonntag (1985) Fundamentals of Classical Thermodynamics’ John Wiley & Sons, Inc., New York ISBN 0-471-82933-1

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