A comprehensive numerical study of battle damage and repairs upon the aerodynamic characteristics of an aerofoil

2010 ◽  
Vol 114 (1158) ◽  
pp. 469-484 ◽  
Author(s):  
M. Saeedi ◽  
F. Ajalli ◽  
M. Mani
Keyword(s):  
Flow Field ◽  
Numerical Solution ◽  
Mesh Generation ◽  
Unstructured Mesh ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Aerodynamic Characteristics ◽  
Experimental Results ◽  
The Other ◽  
Stall Angle

Abstract A NACA 641-412 aerofoil with circle and star damage and also three repair configurations has been numerically investigated. Two different methods of mesh generation were employed: multi structured mesh for the star damaged aerofoil and unstructured mesh for the other aerofoils. The results show that the damage will cause a reduction in lift coefficient of the aerofoil and also a different stall angle relative to that of the undamaged aerofoil. Each kind of repair improves the aerodynamic characteristics of the aerofoil considerably. The flow Field inside the damage hole and the cavity caused by the repair sheets was also investigated. Finally, the numerical solution was qualitatively and quantitatively validated using the available experimental results.

Numerical Study on Aerodynamic Characteristics of NACA0015

2013 ◽  
Vol 302 ◽  
pp. 640-645
Author(s):  
Su Jeong Lee ◽  
Eui Chul Jeong ◽  
Hee Chang Lim
Keyword(s):  
Pressure Distribution ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Surface Pressure Distribution ◽  
Maximum Value ◽  
Stall Angle ◽  
Near Wall

In this study, a numerical simulation is made to understand the effect of the angle of attack on a NACA airfoil, which will be used for a basic shape to apply for making the vertical axis Darius wind turbine. The near-wall y+ value which is less than 1 is known to be most desirable for a near-wall modeling. Therefore, this study is aiming to observe the variation and find the optimized value of y+. The Reynolds number used in this study was 360,000, where the chord length and the velocity were 0.12m and 43.8m/s, respectively. Generally, the lift coefficient of the airfoil tends to increase as the angle of attack increases and it decreases substantially at the stall angle and then it decreases. As expected, the lift coefficient increases rapidly from 0 to 10° and then after the sudden drop of the lift (i.e., the stall) at around 10 to 16° depending on the y+ value. In this paper, it seems to be reliable and appropriate to use y+ value close to 1. From the surface pressure distribution, from the result obtained the ratio of pressure distribution of maximum value to the minimum value was 1.89and these peaks move forward to backward as the angle of attack increases.

scholarly journals Effect of a Circular Slot on Hybrid Airship Aerodynamic Characteristics

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 166
Author(s):  
Sekar Mano ◽  
RadhaKrishnan Ajay Sriram ◽  
Ganesan Vinayagamurthy ◽  
Subramania Nadaraja Pillai ◽  
Amjad Ali Pasha ◽  
...  
Keyword(s):  
Numerical Study ◽  
Flow Behavior ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Suction Side ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Properties ◽  
Slot Opening ◽  
Stall Angle ◽  
High Pressure Region

This numerical study reports the aerodynamic properties of a hybrid airship. The hybrid airships were designed by combining two semi-ellipsoids with a semi-discoid as the base model. From the base model, three different geometrics were identified to study their aerodynamic characteristics. A circular slot was provided between the pressure side and the suction side of the airship. The objective of this study was to realize the flow behavior, aerodynamic characteristics, and stability properties of such slotted hybrid flying vehicles. Interestingly, the results imply that the lift coefficient increases with an increase in the angle of attack for the slotted configurations; this is because the flow separation is delayed due to the slot opening, which in turn is due to the flow of energies from the high-pressure region to the bottom through the slots. The delayed stall angle was 50 degrees, which was 10% more than that of the base model. Aerodynamic characteristics are discussed based on surface pressure, coefficient of lift, and coefficient of drag for various slotted hybrid airships.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

Wind Tunnel Experimental Study of Wind Turbine Airfoil Aerodynamic Characteristics

2012 ◽  
Vol 260-261 ◽  
pp. 125-129
Author(s):  
Xin Zi Tang ◽  
Xu Zhang ◽  
Rui Tao Peng ◽  
Xiong Wei Liu
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Aerodynamic Characteristics ◽  
Wind Turbine Blades ◽  
High Lift ◽  
Minimum Drag ◽  
Stall Angle ◽  
High Reynolds

High lift and low drag are desirable for wind turbine blade airfoils. The performance of a high lift airfoil at high Reynolds number (Re) for large wind turbine blades is different from that at low Re number for small wind turbine blades. This paper investigates the performance of a high lift airfoil DU93-W-210 at high Re number in low Re number flows through wind tunnel testing. A series of low speed wind tunnel tests were conducted in a subsonic low turbulence closed return wind tunnel at the Re number from 2×105to 5×105. The results show that the maximum lift, minimum drag and stall angle differ at different Re numbers. Prior to the onset of stall, the lift coefficient increases linearly and the slope of the lift coefficient curve is larger at a higher Re number, the drag coefficient goes up gradually as angle of attack increases for these low Re numbers, meanwhile the stall angle moves from 14° to 12° while the Re number changes from 2×105to 5×105.

scholarly journals Analysis on Flow Field Characteristics of Airfoil in Pitching Motion

2021 ◽  
Vol 2076 (1) ◽  
pp. 012069
Author(s):  
Rui Yin ◽  
Jing Huang ◽  
Zhi-Yuan He
Keyword(s):  
Flow Field ◽  
Drag Coefficient ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Decisive Role ◽  
Aerodynamic Characteristics ◽  
Pitching Motion ◽  
Maximum Value ◽  
Flow Field Characteristics ◽  
Lift And Drag

Abstract Based on CFD, the flow field characteristics of NACA4412 airfoil are analyzed under pitching motion, and its aerodynamic characteristics are interpreted. The results show that streamline changes on the upper surface of the airfoil play a decisive role in the aerodynamic characteristics. The interaction between the vortex leads to fluctuations in the lift and drag coefficients. Under a big angle of attack, the secondary trailing vortex on the upper surface of the airfoil adheres to the trailing edge of the airfoil, resulting in an increased drag coefficient. Under a small angle of attack, the secondary trailing vortex can break away from the airfoil. The lift coefficient reaches the maximum value of 2.961 before the airfoil is turned upside down, and the drag coefficient reaches the maximum value of 1.515 after the airfoil is turned upside down, but the corresponding angles of attack of the two are equal.

scholarly journals Aerodynamic Performances of Paper Planes

2020 ◽  
Vol 77 (1) ◽  
pp. 124-131
Author(s):  
Noor Iswadi Ismail ◽  
Zurriati Mohd Ali ◽  
Iskandar Shah Ishak ◽  
R.M. Noor ◽  
Rosniza Rabilah
Keyword(s):  
Lift Coefficient ◽  
The Other ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Aerodynamic Efficiency ◽  
Ansys Cfx ◽  
Wide Range ◽  
Aerodynamic Performances ◽  
Paper Plane ◽  
Stall Angle

Paper plane has a high potential to be upgraded as a Micro Air Vehicle (MAV). Due to its simplicity, paper plane offers easier design option compared to the biological inspired designs as shown in recent MAV development. However, researchers have underestimate and overlook the basic aerodynamic performance induced by these paper planes. This is due to its common usage as toys and wide range of paper plane design. Thus, the objective for current work is to analyse and compare the aerodynamics forces and its performance for selected paper plane design known as Glider, Wide Stunt Glider Plane and Stunt plane. A series of CFD simulations on each paper plane was executed by using ANSYS-CFX module. A steady state, incompressible flow Navier-Stokes equation (RANS) combined with Shear Stress Turbulence (SST) model were used in this works to solve flow problem over the paper planes. The analysis is mainly conducted to study and compare the lift coefficient (), drag coefficient ()and aerodynamic efficiency () performances for each paper planes. The results show that the Glider paper plane has managed to produce better performances in terms overall magnitude, stall angle, wider angle of attack (?) envelope and higher maximum lift coefficient magnitude compared to the other paper plane design. However, Glider paper plane has the least distributions by producing at least 14.3% larger magnitude compared to the other plane design at certain ? region. Instead, The Wide Stunt has promisingly produced better distribution by producing lower value compared to the other plane design. Based on performance, the Wide Stunt paper plane has produced better and maximum aerodynamic efficiency () magnitudes compared to the other design. Wide Stunt paper plane induced at least 6.4% better magnitude compared to the other paper plane design. Based on these results, it can be concluded that Wide Stunt paper plane has promising advantages which are very crucial for the paper plane especially during hovering operation, take-off and landing manoeuvre.

Numerical Study of the inside Flow Field and the Rectangle Channel Impeller of Roto-Jet Pump

2014 ◽  
Vol 529 ◽  
pp. 164-168 ◽  
Author(s):  
Wei Zang ◽  
Xin Cheng Li ◽  
Yi Chen ◽  
Yu Ting Luo
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Numerical Study ◽  
The Other ◽  
Jet Pump ◽  
Hydraulic Models ◽  
Flow Channels ◽  
Ansys Cfx ◽  
Angle Blade

By means of ANSYS-CFX, the 3D numerical simulations of flow field for the three hydraulic models are performed. Through comparing the three types of pumps with three different rectangle channel impellers which have different spread angle, blade, the authors draw conclusions: the distribution of the pressure and velocity in the rectangle flow channels with 6° spread angle is well-proportioned, the head and the efficiency of the whole pump can meet the requirement: But the other two types of impeller channels, the distribution of velocity is unstable, there are backflow and big whirlpool. Therefore, the rectangle channel impeller with 6°spread angle is a better type for the Roto-Jet pump.

Selection of Airfoils for Straight-Bladed Vertical Axis Wind Turbines Based on Desirable Aerodynamic Characteristics

2008 ◽  
Author(s):  
Mazharul Islam ◽  
M. Ruhul Amin ◽  
David S.-K. Ting ◽  
Amir Fartaj
Keyword(s):  
Urban Areas ◽  
Lift Coefficient ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Performance Indices ◽  
Niche Markets ◽  
Design Changes ◽  
Stall Angle ◽  
Lift And Drag ◽  
Selection Of

Selection of the airfoil is crucial for better aerodynamic performance and dimensions of a smaller-capacity SB-VAWT which can compete with conventional energy sources in niche markets like urban areas and off-grid remote applications for diversified applications. Airfoil related design changes also have the potential for increasing the cost effectiveness of VAWTs. Recently, Islam et. al [1] have identified the desirable features of an ideal airfoil for smaller capacity SB-VAWT to improve its starting characteristics and overall performance. They have shortlisted several aerodynamic characteristics of the desirable airfoil. Based on these desirable aerodynamic characteristics, an attempt has been made in this paper to shortlist ten prospective candidate airfoils for smaller-capacity SB-VAWT. This is done using both experimental and analytical characteristics. Nine performance indices have been defined in this paper in light of desirable aerodynamic characteristics to select best performing airfoil. These performance indices are utilized for considering the following desirable aerodynamic characteristics: (i) stall angle at low Reynolds number, (ii) width of the drag bucket, (iii) zero-lift-drag coefficient, (iv) Cl/Cd ratio, (v) maximum lift-coefficient, (vi) deep-stall angle, (vii) roughness sensitivity, (viii) trailing edge noise generation, and (ix) pitching moment. Here, Cl and Cd are coefficients of lift and drag respectively. After determining the value of the performance indices and rating of the candidate airfoils, the most promising airfoil is selected. Among the ten candidate airfoils, overall rating of NASA LS(1)-0417 has been found to be the best.

scholarly journals Initial development of the hybrid semielliptical-dolphin airfoil

2021 ◽  
pp. 234-234
Author(s):  
Zorana Dancuo ◽  
Ivan Kostic ◽  
Olivera Kostic ◽  
Aleksandar Bengin ◽  
Goran Vorotovic
Keyword(s):  
Lift Coefficient ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Calculation Model ◽  
General Aviation ◽  
The Other ◽  
Aviation Industry ◽  
Initial Development ◽  
Other Hand ◽  
Nose Shape

Iosif Taposu has formulated a mathematical model and generated a family of airfoils whose geometry resembles the dolphin shape. These airfoils are characterized by a sharp leading edge and experiments have proven that they can achieve better aerodynamic characteristics at very high angles of attack than certain classical airfoils, with the nose geometry inclined downwards. On the other hand, they have not been applied to any commercial general aviation aircraft. The authors of this paper have been motivated to compare the aerodynamic characteristics of widely used NACA 2415 airfoil with Taposu?s dolphin that would have the same principal geometric characteristics. A CFD calculation model has been established and applied on NACA 2415. The results were compared with NACA experiments and very good agreements have been achieved in the major domains of lift and polar curves. The same CFD model has been applied on the counterpart Dolphin 2415. Results have shown that the Dolphin has a slightly higher lift/drag ratio in the lift coefficient domain 0.1 ? 0.35 than NACA. On the other hand, at higher and lower lift coefficients, its aerodynamic characteristics were drastically below those of the NACA section, due to the unfavorable influence of the Dolphin?s sharp nose. A series of the Dolphin?s leading edge modifications has been investigated, gradually improving its aerodynamics. Finally, version M4, consisting of about 70% of Dolphin?s original rear domain and 30% of the new nose shape, managed to exceed the NACA?s characteristics, thus paving the way to investigate the Dolphin hybrids that could be suitable for the general aviation industry.

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