The Unlimited Power and Potential of Energy from Wind - Research Paper Example

AIRFOIL Name University November 2015 Abstract The main aim of the experiment is to provide details simulation using ANSYS fluent 15.0. The simulation as produced graphs for attack angles 20 and 0 showing position verses velocity magnitude of the airfoil. The results shows that at an attack angle of 20 the highest velocity is 18.4m/s and the lowest velocity is 12.4m/s. it shows that the alteration of attack angles and surface leads to change in velocity of the airfoil. The pressure appears to have effect on the chord position. Table of Contents Abstract 2 Introduction 4 Computational Details 4 Results and discussion 5 Conclusion 12 References 14 Introduction Wind has the energy and power to holder the direction of airfoil as well as velocity magnitude of the same. The performance of an airfoil in the wind is usually affected by many factors among them an attack angle. In this case we are going to study the effect of attack angle on airfoil velocity magnitude. Numerical simulation as been used to provide accurate prediction and the velocity magnitude of the foil and different attack angles as well as different surfaces. In the simulation 20o and 0o attack angle have been considered under high pressure and suction surface. this surfaces has been used because the flow of the airfoil in air is complex and shows different phenomena when surface changes as well as boundary layers. This is why we have used CFD which is large –eddy simulation that provides a range of turbulence scales. A large eddy simulation has the capability of fully simulating all the fluctuations which are large than the mesh size. The grid allows as calculating and making complex figures which will be difficult under normal circumstances. Computational Details The first step is to design a ‘Mesh’ in FDS. A ‘Mesh’ is an open space; where the airfoil will be modeled in it. The Mesh was designed by using the above command; it determined the dimensions along (X, Y, Z) axes; in addition to the number of cells required in each direction (X, Y, Z). The 2D geometry simulation has been used in designing a solver for this case. This experiment requires the instauration of the airfoil where wind will be controlled as well as pressure. Then attack angles of 0o, 4o, 8o, 160, and 20o have been selected for domain selection size of 6c 2.44c. FDS modelling technique gives a temporal resolution that plays a vital in the evaluation of entrainment. The simulation has the capability of fully simulating all the fluctuations which are large than the mesh size. When an estimation is being made for smaller eddies there is little uncertainties due to the fact that the eddies are of a uniform character. (FDS) will provide a lot of Data Recording; some are considered and some are not. Data and recordings which are related to; static pressure, velocity magnitude and position of airfoil. Results and discussion The result in this study is from data processed by ANSYS fluent 15.0. it should be noted that the static pressure changes with the chord position and the surface. The result also shows that the chord position is also affected weather high pressure or low pressure. From the result the graph below shows the velocity magnitude in m/s of a foil when they attack angle is 0o. The second graph below shows the stream wise velocity as predicted by CFD in case when the attack angle is 0o the flow or velocity magnitude is haphazard as compared to when it is 20o when the attack angle is 20o the magnitude is 18.4 m/s while the low velocity attack point is 0.1m/s it was also found out that the low velocity was achieved when the attack angle was zero. 0 degrees Figure 1: attack of 0 degrees The graph above shows the stream wise velocity of profiles at 0o attack angle where the velocity magnitude seems to be 18.4mf and the lowest seems to be 12.1mf this result does not show pressure distribution of the airfoil. The oncoming forms angle of an attack of an airfoil. If the angle of attack is great it means there will be a great lift. This means the angle of attack determines the lift of an airfoil. However, it should be noted that an airfoil at a certain attitude due to the negative angle of attack of the aerofoil enabling the airfoil to have a zero lift Figure 2: attack angle of 20 degrees In considering lift coefficient is calculated using angle of attack. The measured velocity magnitude can then be related to a position, airfoil. The airfoil itself is tilted as if it were travelling over an inclined surface. Because of the shape of the airfoil, an aerodynamic force called lift acts upward when the airfoil is in level flight. To go round a turn, the airfoli are titled; the lift force stays perpendicular to the wings and therefore, now has a horizontal component. Just as the normal force has a horizontal component supplies the necessary radial acceleration, while the vertical components of the lift hold the it up. Therefore, And Where the x-axis is horizontal and the y-axis is vertical. The lift force is different in its physical origin from the normal force. Figure 3: From the diagrams below it can be noted that the angle of attack of 0 degrees and below have a lower lift that is decreasing at the similar pace. However, the critical angle of attack appears to be 20 degrees where air is bend due to viscosity, that is, air is separated from the airfoil. Figure 4: From the plots above it can be noted that angle of zero lift is 0o and the angle gives maximum lift is 200. If it flies upside down, the maximum lift is 8, and at what angle is 20 Using the Newton’s law of forces and moments acting on an airfoil, we find the following equations necessary Where Y is pressure force per unit span. This can further reduced by subtracting p for both sides of the foil i.e upper and lower side pressure values, leaving , This equation will then be non-dimensionalized as Where c is chord and the other is dynamic pressure then, Lift and Drag: Lift and drag are related to the X- and Y- forces as follows: Where Cl the lift, and Cd is drag coefficients A two－dimensional flow past a airfoil placed in a turbulent boundary ’layer is described with special reference to the lift and drag forces acting on the airfoil. A theoretical analysis of the flow is made for the hypothetical in viscid shear flow with a linearly varying velocity profile, and experiments were performed with a airfoil placed in an artificially produced shear flow and in a turbulent boundary layer, respectively. An explicit solution for the stream function that describes a uniform shear flow past an airfoil subjected to an interference of a wind was obtained. It was found from detailed numerical calculations that static pressure decreases as the distance between the airfoil and the position changes decreases. The lift force acting on the airfoil calculated by numerically integrating the pressure on the surface of the cylinder was found to be positive. When there exists a certain amount of velocity gradient in the transverse direction of flow, which is similar to the　case of a practical boundary layer that develops along a stationary boundary. it was verified that an acceptable agreement between the theory and the experiment was found concerning the stagnation pressure and the position of stagnation point respectively provided that the clearance between the airfoil and wind. Conclusion Velocity magnitude flow has been done under two different conditions that are zero and 20o. a Reynolds number of 900000 has been determined under this velocities. The result for 20o shows that the experiment data and validated data have a number of similarities.Determining the transverse velocities along a particular cross section by the measurement of pressure heads and the application of the Bernoulli’s principle in determining the velocities were done successfully. The graphical representation of the velocities at various positions over the position helped understand the basis of how a boundary layer is formed and how it affects the flow process. The graphical comparison of these values with Reynold's number was also done successfully. References Daugherty, R. L and Franzini, J. B. (1965). Fluid Mechanics, (6th ed). New York: McGraw-Hill McGraw-Hill Companies. (2005). Boundary-layer flow. McGraw-Hill Concise Encyclopedia of Physics (5th ed.). The McGraw-Hill Companies, Inc. Spink, L. K. (1967). Principles and Practice of Flowmeter Engineering. The Foxboro Company. Foxboro, MA. Read More

Results and discussion

The result in this study is from data processed by ANSYS fluent 15.0. it should be noted that the static pressure changes with the chord position and the surface. The result also shows that the chord position is also affected whether high pressure or low pressure.

From the result, the graph below shows the velocity magnitude in m/s of a foil when the attack angle is 0o. The second graph below shows the streamwise velocity as predicted by CFD in the case when the attack angle is 0o the flow or velocity magnitude is haphazard as compared to when it is 20o when the attack angle is 20o the magnitude is 18.4 m/s while the low-velocity attack point is 0.1m/s it was also found out that the low velocity was achieved when the attack angle was zero.

The graph above shows the stream-wise velocity of profiles at 0o attack angle where the velocity magnitude seems to be 18.4mf and the lowest seems to be 12.1mf this result does not show the pressure distribution of the airfoil. The oncoming forms angle of an attack of an airfoil. If the angle of attack is great it means there will be a great lift. This means the angle of attack determines the lift of an airfoil. However, it should be noted that an airfoil at a certain attitude due to the negative angle of attack of the aerofoil enabling the airfoil to have a zero lift.

In considering lift coefficient is calculated using the angle of attack. The measured velocity magnitude can then be related to a position, airfoil.

The airfoil itself is tilted as if it were travelling over an inclined surface. Because of the shape of the airfoil, an aerodynamic force called lift acts upward when the airfoil is in level flight. To go round a turn, the airfoil is titled; the lift force stays perpendicular to the wings and therefore, now has a horizontal component. Just as the normal force has a horizontal component supplies the necessary radial acceleration, while the vertical components of the lift hold it up.

From the diagrams below it can be noted that the angle of attack of 0 degrees and below have a lower lift that is decreasing at a similar pace. However, the critical angle of attack appears to be 20 degrees where the air is bend due to viscosity, that is, the air is separated from the airfoil.

A two－dimensional flow past an airfoil placed in a turbulent boundary ’layer is described with special reference to the lift and drag forces acting on the airfoil. A theoretical analysis of the flow is made for the hypothetical inviscid shear flow with a linearly varying velocity profile, and experiments were performed with an airfoil placed in an artificially produced shear flow and in a turbulent boundary layer, respectively. An explicit solution for the stream function that describes a uniform shear flow past an airfoil subjected to the interference of wind was obtained. It was found from detailed numerical calculations that static pressure decreases as the distance between the airfoil and the position change decreases. The lift force acting on the airfoil calculated by numerically integrating the pressure on the surface of the cylinder was found to be positive. When there exists a certain amount of velocity gradient in the transverse direction of flow, which is similar to the　case of a practical boundary layer that develops along a stationary boundary.

it was verified that an acceptable agreement between the theory and the experiment was found concerning the stagnation pressure and the position of stagnation point respectively provided that the clearance between the airfoil and wind.

Conclusion

Velocity magnitude flow has been done under two different conditions that are zero and 20o. a Reynolds number of 900000 has been determined under these velocities. The result for 20o shows that the experiment data and validated data have a number of similarities. Determining the transverse velocities along a particular cross-section by the measurement of pressure heads and the application of Bernoulli’s principle in determining the velocities were done successfully. 

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