Aerodynamics Analysis on Unsymmetrical Fuselage Models

2013 ◽  
Vol 315 ◽  
pp. 273-277
Author(s):  
Mohd Ridh bin Abu Bakar ◽  
Bambang Basuno ◽  
Sulaiman Hasan
Keyword(s):  
Cross Section ◽  
Strong Influence ◽  
Lift Coefficient ◽  
Circular Cross Section ◽  
Longitudinal Axis ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Symmetrical Body ◽  
Semi Empirical ◽  
Plat Form

The large commercial passengers airplanes are mostly designed to have symmetrical body with respect to the longitudinal axis. However for small passengers airplanes or for the airplane designed as UAV plat form is normally having an unsymmetrical fuselage. The aerodynamics characteristics fuselage may give a strong influence to the overall aerodynamics characteristics of the airplane. The present work investigates the aerodynamics characteristics of the unsymmetrical fuselage with respect to the longitudinal axis. The fuselage assumed to have circular cross section and the coordinate of the fuselage are created by using the same equation which had been used in defining the coordinate of cambered airfoil NACA series four digits. The fuselage had been set to have the same maximum thickness 15 % of the fuselage length and different fuselage models are obtained through varying the position as well as the value of the maximum camber line. The semi empirical aerodynamic method for estimating the fuselage lift coefficient CL, drag coefficient CDand the fuselage pitching moment coefficient CMsuch as given by DATCOM are well established. However when it came to the unsymmetrical fuselage, this approach can not be adopted easily. The required of angle attack at zero lift of the corresponding unsymmetrical fuselage is difficult to define. The result for particular cambered fuselage indicates that the aerodynamics characteristics strongly influenced by how the fuselages camber lines look likes.

The Aerodynamics Analysis on Cambered Fuselage Model

2014 ◽  
Vol 660 ◽  
pp. 492-497
Author(s):  
Mohd Zarif bin Md Shah ◽  
Mohd Ridh bin Abu Bakar ◽  
Bambang Basuno
Keyword(s):  
Cross Section ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Circular Cross Section ◽  
Pitching Moment ◽  
Line Thickness ◽  
Moment Coefficient ◽  
Definition Of

There various factors gives influence in determining the fuselage shapes, such as the payload, cockpit, wing and tail placements or in manner up and down loading the payload for a cargo aircraft. These factors may come up the fuselage is no longer as symmetrical fuselage but represent as a cambered fuselage. As results the lift coefficient as well as its pitching moment coefficient is no longer equal to zero as the angle of attack goes to zero. Basically the manner how to determine the fuselage aerodynamics characteristics for cambered fuselage can be done in similar way as in the case of symmetrical fuselage by simply replacing the angle of attack α term with (α-αL=0), where αL=0 represent the angle of attack at zero lift. The present work use a similar manner in determining the zero lift angle of attack as it had been used in DATCOM software. To investigate the effect of camber on the aerodynamics characteristic fuselage, the present work use a fuselage model with a circular cross section where the location of center of the circle placed along the fuselage’s camber line. The fuselage’s camber line defined according to the definition of camber line of NACA airfoils. Aerodynamics analysis on over various fuselage models indicate that the maximum camber line thickness and their position give a significant influent to the fuselage aerodynamics characteristics.

Analytic and Experimental Investigation of Dihedral Configurations of Three-Winglet Planforms

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
David S. Miklosovic
Keyword(s):  
Aspect Ratio ◽  
Lift Coefficient ◽  
Pitching Moment ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Moment Coefficient ◽  
Velocity Circulation ◽  
Low Speed Wind Tunnel ◽  
Experimental Effort ◽  
Good Agreement

An analytic and experimental effort was undertaken to assess the effectiveness and efficiency of three winglets mounted chordwise to the tip of a rectangular wing. The winglets, with an aspect ratio of 4.6, were mounted on a half-span wing having an effective aspect ratio of 6.29. 13 configurations of varying dihedral arrangements were analyzed with a vortex lattice method and tested in a low-speed wind tunnel at a Reynolds number of 600,000. While the analytic method provided fair agreement with the experimental results, the predicted trends in lift, drag, and (to a lesser degree) pitching moment were in good agreement. The analytic distributions of wake velocity, circulation, and downwash angle verified that highly nonplanar configurations tended to reduce and diffuse the regions of highest circulation and to create more moderate downwash angles in the wake. This was manifest as an overall drag reduction. More specifically, the results showed that the winglets could be placed in various optimum orientations to increase the lift coefficient as much as 65% at the same angle of attack, decrease the drag coefficient as much as 54% at the same lift coefficient, or improve the maximum L∕D by up to 57%. The most dramatic findings from this study show that positioning the winglet dihedral angles had the result of adjusting the magnitude and slope of the pitching moment coefficient. These observations suggest that multiple winglet dihedral variations may be feasible for use as actively controlled surfaces to improve the performance of aircraft at various flight conditions and to “tune” the longitudinal stability characteristics of the configuration.

Hydrodynamical Analysis on the Arrow

2014 ◽  
Vol 644-650 ◽  
pp. 527-530
Author(s):  
Ji He Zhou ◽  
Xiao An Long
Keyword(s):  
Lift Force ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Static Stability ◽  
The State ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Attached Flow ◽  
Main Components

The water tunnel and wind tunnel test carried on the arrow aims to have a better understanding of the hydrodynamics performance of arrows and to improve the technical knowledge of the archery movement Through the experimental research, we can draw conclusions as follows: within the range of angle of attack ( -6°---6°), the arrow can keep the state of attached flow: The state of flow of the arrow with spiral plastic pinna is better than that of arrow with straight one; Within the experimental angle of attack, the lift coefficient Cy will become larger with the pitching moment coefficient Mz getting smaller with the increase of the angle of attack. The arrow has the vertical static stability; with or without arrow feather will have great impact on lift force Y and pitching moment coefficient Mz; the feather rolling will have some impact on lift coefficient Cy, The arrow feather is the main components to produce lift force Y and to give the arrow body relatively great static stability.

scholarly journals Influence of rotatory inertia on stochastic stability of a viscoelastic rotating shaft

2008 ◽  
Vol 35 (4) ◽  
pp. 363-379
Author(s):  
Ratko Pavlovic ◽  
P. Kozic ◽  
G. Janevski
Keyword(s):  
Cross Section ◽  
Stochastic Stability ◽  
Circular Cross Section ◽  
Longitudinal Axis ◽  
Physical Parameters ◽  
Rotatory Inertia ◽  
Rotating Shaft ◽  
Axial Forces ◽  
Constant Rate ◽  
Mean And Variance

The stochastic stability problem of a viscoelastic Voigt-Kelvin balanced rotating shaft subjected to action of axial forces at the ends is studied. The shaft is of circular cross-section, it rotates at a constant rate about its longitudinal axis of symmetry. The effect of rotatory inertia of the shaft cross-section and external viscous damping are included into account. The force consists of a constant part and a time-dependent stochastic function. Closed form analytical solutions are obtained for simply supported boundary conditions. By using the direct Liapunov method almost sure asymptotic stability conditions are obtained as the function of stochastic process variance, external damping coefficient, retardation time, angular velocity, and geometric and physical parameters of the shaft. Numerical calculations are performed for the Gaussian process with a zero mean and variance ?2 as well as for harmonic process with amplitude H.

Numerical Calculation of a Missile's Aerodynamic Characteristic

2011 ◽  
Vol 186 ◽  
pp. 220-224
Author(s):  
Chun Guo Yue ◽  
Xin Long Chang ◽  
You Hong Zhang ◽  
Shu Jun Yang
Keyword(s):  
Numerical Calculation ◽  
Drag Coefficient ◽  
Numerical Computation ◽  
Aerodynamic Characteristic ◽  
Lift Coefficient ◽  
Shape Design ◽  
Pitching Moment ◽  
Moment Coefficient ◽  
Mach Numbers ◽  
In Virtue Of

In virtue of Fluent of CFD software, numerical computations of aerodynamics of an air-to-air missile in different mach numbers and different attack angles were carried though. The movement trends of lift coefficient, drag coefficient and pitching moment coefficient with variety of mach numbers and attack angles were gained, meanwhile, distributing trends of pressure, temperature and weather velocity were also obtained. The results indicated that the basis and references could be offered by numerical computation results for shape design of missile and definite preponderances were showed than traditionary numerical computation methods.

Aerodynamic Characteristic Analysis of Two-Dimensional Trajectory Corrector Projectile in Mortar

2014 ◽  
Vol 624 ◽  
pp. 236-239
Author(s):  
Tong Zhang ◽  
Xiao Li Zhao ◽  
Zhen Dong Song
Keyword(s):  
Aerodynamic Characteristic ◽  
Lift Coefficient ◽  
Simulation Models ◽  
Future Research ◽  
Pitching Moment ◽  
Two Dimensional ◽  
Characteristic Analysis ◽  
Data Simulation ◽  
Moment Coefficient ◽  
Simulation Results

Aiming at researching aerodynamic characteristic of projectiles. This paper builds three simulation models with fins in different amount and appearance, by using CFD software to generate meshes of each model, it simulates the changing laws of drag coefficient, lift coefficient and pitching moment coefficient and analyses correct ability and flight stability of each model according to the data, simulation results indicate that projectile with folded fins have better aerodynamic appearance and can be studied deeper, it provides aerodynamic reference for future research.

scholarly journals Numerical Simulation of the Aerodynamic Influence of Aircrafts During Aerial Refueling with Engine Jet

2019 ◽  
Vol 21 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Yi Li ◽  
Yang Zhang ◽  
Junqiang Bai
Keyword(s):  
Stokes Equations ◽  
Dynamic Pressure ◽  
Lift Coefficient ◽  
Jet Flow ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Pitching Moment ◽  
Aerial Refueling ◽  
Rolling Moment ◽  
Moment Coefficient

Abstract Aerial refueling technology has been widely applied in various fields and it is one of the hotspots but difficulties for the aeronautical technologies. DLR-F6 WBNP model is used as a tanker and a fighter model is used as a receiver. The flow field of Probe–Drogue refueling and Flying Boom refueling is numerically simulated using the Reynolds-averaged Navier–Stokes equations, and the effects of the jet flow and the aerodynamic characteristics of the receiver are taken into consideration. The results indicate that the effect of downwash of the tanker reduces the lift coefficient and decreases the pitching moment coefficient of the receiver. The jet flow of tanker increases the dynamic pressure while decreases the local angle of attack, which increases the pressure difference between the upper and lower surfaces of receiver. Compared with the results without jet, the jet flow can increase the lift and the drag of the receiver and reduces the pitching moment, and even cause the change of rolling moment direction. Therefore, engine jet is an important factor when simulating aerial refueling.

A Wind Tunnel Investigation of a Thin Aerofoil with a Sharp Leading Edge, and Blowing Applied at the Mid-Chord at Two Angles Relative to the Surface

1966 ◽  
Vol 70 (666) ◽  
pp. 665-669 ◽  
Author(s):  
I. Wygnanski
Keyword(s):  
Separation Bubble ◽  
Lift Coefficient ◽  
Leading Edge ◽  
Pitching Moment ◽  
Appreciable Change ◽  
Low Mach Number ◽  
Moment Coefficient ◽  
Edge Separation ◽  
Jet Blowing ◽  
Sharp Leading Edge

SummaryExperiments have been made on a thin two-dimensional aerofoil with sharp leading edge and with a jet blowing through a mid-chord slot on the upper surface in order to control the boundary layer and circulation around it. The measurements were made at low Mach number. The effect of changing the angle of blowing was studied in anticipation that this would help to control the leading edge separation bubble. It transpired that variation of the blowing angle caused little change in lift coefficient but produced an appreciable change in moment coefficient. A low pressure separation bubble was formed downstream of the slot with the jet discharging at an angle and subsequently re-attaching to the surface. This reduced the nose-up pitching moment about the quarter-chord point. The experimental results are in fair agreement with the “jet-flap” and jet entrainment theory.

Aerodynamic Investigation of Hypersonic Vehicle with Forward-Facing Cavity

2011 ◽  
Vol 108 ◽  
pp. 41-47 ◽  
Author(s):  
Hai Bo Lu ◽  
Wei Qiang Liu
Keyword(s):  
Drag Coefficient ◽  
Thermal Protection ◽  
Aerodynamic Force ◽  
Lift Coefficient ◽  
Characteristic Parameter ◽  
Aerodynamic Performance ◽  
Hypersonic Vehicle ◽  
Attack Angle ◽  
Pitching Moment ◽  
Moment Coefficient

Forward-facing cavity mounted on the blunt nose of hypersonic vehicle is a good choice to reduce the stagnation heating. Presently, the study on hypersonic vehicles nose tip with forward-facing cavity mainly focus on its thermology characteristic, and little work can be found investigating the effect of cavity on aerodynamic force for a holistic vehicle. The CFD method is developed to investigate the effect of cavity geometry on aerodynamic performance of hypersonic vehicle with a forward-facing cavity on the nose-tip. Drag coefficient, lift coefficient and pitching moment coefficient of the vehicle for different attack angle are calculated. It is found that the cavity length to diameter (L/D) can not be a characteristic parameter in aerodynamic research, though it was used as a main characteristic parameter in investigation on the thermal protection. The length of the cavity L has little effect on aerodynamic characteristic of the vehicle, and the cavity diameter D has a crucial influence on the aerodynamic performance and the aerodynamic performance decrease with the D increasing. With the attack angle increasing, the drag coefficient, lift coefficient, pitching moment coefficient and lift-drag ratio of the hypersonic vehicle all increase.

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