Wind Definition and 829 Threads

I'm building a yaw control system for one of the universitys VAWT turbines. I need to design a slewing bearing which can reliably support radial, axial and tilting moments. I have absolutely no idea how to do this or even where to start. Could you please give me some advice as to go about...

Homework Statement How should the thrower adjust the angles of launch if he is throwing the object into a velocity of 40 m/s wind? Homework Equations N/A The Attempt at a Solution I really have no idea. Personally, I think throwing the object at a lower angle would help throwing...

I was reading an earlier post about having a wind turbine embedded in a vehicle to generate electricity as it moved. I came to this site after having this thought last night. But I realized immediately that drag and weight would be counterproductive. However, I did ponder an alternative...

Does anyone know of any simple aerodynamics simulators? Preferably one that would allow me to import a 3D model and then calculate its drag coefficient? I have done a few searches, but failed to find much of anything. Oh, and it needs to be free. Not part of some mutli-hundred dollar...

Hello Friends. I have a question that may have to do with wind lift and other effects. I have two wooden poles set into the ground. Both poles are upright and has a height of H feet. The horizontal separation of these poles is S feet. Let's say I attach a rope in between these poles so that...

What does happen to the wind after it passes through a wind turbine blade? Does it increases the wind speed?

This thread is for MATH regarding wind powered vehicles. I don't want to see your opinion. I want facts and math. PERIOD This is my (attempted) derivation of what a wind powered car is capable of. I may have accidentally derived an infinite energy machine, so if someone would check my work...

Hi everyone! I am new in physics forum and this is my first post. I need help from the people out there. I wanted to deisgn a Vertical Axis wind turbine to produce 5k Watt output with a frequecy of 50Hz, 220VAC, to completely run my home appliance 24 hours. Appliances include: -1.5ton...

One of the all-time great science mysteries is now a step closer to explanation. The surface of the sun, known as the photosphere, can reach temperatures of 5,000 degrees. To many it would seem logical that the temperature would lower further away from the sun. But, the outer atmosphere, known...

Homework Statement An airplane has an airspeed of 145 km/h. it is to make a flight in a direction of 72 degees while there is a 32-km/h wind from 342 degrees. what will the airplane's actual heading be? Homework Equations trig functions The Attempt at a Solution this is a calc3...

I'm trying to model a vertical axis wind turbine with the double-multiple streamtube model (with Matlab), where wind speed is dampened by an induction factor so that the output is different for upwind and downwind parts of rotation. The trouble is that for the downwind part, the induction...

At the current rate of oil consumption, the world will run out of it in twenty years. The Netherlands is investing somewhat into wind energy since that's one of the few renewable resources around in our country. Now the obvious problem with wind energy is that it is unreliable, so people are...

hey! Wind turbines have got certain threshold speed of wind (of about 6-7 m/s) which acts as a mechanical resistance to its rotation. Is this mechanical resistance a result of frictional resistance in bearings alone, or it is also a result of its own weight? If yes, approximately how much...

I recently read this http://www.earthtechling.com/2011/06/wind-turbines-board-europe-ferries/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Earthtechling+%28EarthTechling%29&utm_content=Google+Reader" and it's really bugging me. They claim that by putting wind turbines on the...

Hello! I am new and recently figured out how to make wind tunnels in 3ds max and Maya. Im helping to develop a sci-fi game and just out of curiosity took one of our spaceship models meant for space to planet travel into the wind tunnel to see if it would really be able fly, and if not, find out...

http://www.sauerenergy.com/index.php?option=com_content&view=article&id=50 The link above gives a picture and rough model of a Sauer Wind Turbine. I was wondering, since the dimples on the turbine were based on the idea that a golf ball reduced air resistances, how it would help the wind...

To calculate the force of wind I use the following simple method: Speed in mph^2 x .0027 = psf. Anyone know of a simple method of calculating psf using the speed of water? Please.

Greetings, for the school I must find some information about the building of a small close wind tunnel . Some one know where to find it? Good day!

Homework Statement A wind turbine is initially spinning at a constant angular speed. As the wind's strength gradually increases, the turbine experiences a constant angular acceleration 0.127 rad/s2. After making 2790 revolutions, its angular speed is 155 rad/s. (a) What is the initial angular...

Homework Statement A sailboat is traveling east at 5.0 m/s. A sudden gust of wind gives the boat an acceleration a =(0.80 m/s^2 and 40 degrees north of east). Homework Equations V = Vo + at X - Xo = Vo*t + .5at^2 V^2 = Vo^2 + 2a(X - Xo) The Attempt at a Solution I...

Homework Statement Air of density 1.2kgm-3, speed 8ms-1 is incident on blades of wind turbine. Radius of blades 1.5m. After passing blades, wind speed is reduced to 3.0ms-1 and density 1.8kgm-3. How much power is extracted from wind?Homework Equations P=1/2 pAv3The Attempt at a Solution P=1/2 x...

Can wind disrupt TV reception in any way other than the two most obvious ways: 1) blowing the receiving antenna out of alignment, and 2) blowing obstacles like trees into the path of the signal? I would think the actual air currents would be invisible to the radio waves...am I wrong?

Hello all, I am not an engineer, but I am a 32 year steel fabricator, I have recently built a 17 foot wind turbine with an axial flux alternator, I would like to build a tower for it but would like to get a general idea before I go to a local engineer for actual stamped drawings which are...

Hello. The title of this post may seem too hardcore. Actually, I am building a simple wind turbine made from wood and aluminium thin plate. it has three blades and 120 cm in diameter. It should be at least 3.5 m above ground, on a steel/wood column. I have no idea how to install this pole...

I am making a wind tunnel to test the lift of an airfoil when chaning the variables of angle of attack and air velocity. For a good EEI I need more then 3 speeds. However, all the people I know only have 3 speed fans, I don't know how to get more speeds as the wind tunnel gets built around the...

Homework Statement I am trying to determine the input I will have on a shaft with a continuous force of 3,720 pounds one foot out from the shaft center. I am thinking the input continuous torque would be 1 foot being that I am using a 2 foot pulley on the shaft, and I have a continuous...

I want to know that how is govering is executed in case of wind mill to ensure that generator's shaft rotates at constant speed so as to generate electricity at fixed frequncy. Like in case of hydroturbine, governing is done by regulating water flowrate.

This curiosity began with my attempt to find a general simplified formula for wind force displaced perpendicular to a surface with relation to the velocity of wind and the area of the surface {analogous to the simple models in UP 1 for describing motion}. This curiosity had its orgins with...

I just read up on this and I am wondering if this person could be correct. He believes that winds are created by convection currents created by the heating and cooling of air. The air over a warmer ocean coming in contact with cooler air over land or vise versa. Now he says that these effects...

I have done a lab experiment, to determine the coefficient of lift for an aerofoil, keeping the angle of attack constant. The equation I have used is Lift= (1/2) v times v times A times ρ times Coefficient of lLift v= Velocity of air ρ=air density A= planform area to give...

Hi everyone. This is my first time trying this. So please be gentle. My question is to do with a dc motor. I want to build a wind generator and I am trying to figure out what size motor to start with and try to size the blades to get the best out of it. I know that their is a lot of other...

Imagine that i have a source of _constant_ wind. It travels, with negligible variance, at 50 mph. The problem is that at the accessible point, the source of the wind has an opening of only 1 meter across. (Basically, at this point, imagine a small wind tunnel). The question is, how much...

Hi I wasn't sure whether this is technically homework or not but anyway. I am building a miniature wind turbine for a basic project just for myself. I was wondering if there was anyway for working out the voltage gained from the generator. I know this could be gained from using P = IV but...

Homework Statement My son and I have built a wind turbine following the plans on: Build your own Wind Turbine Designed by Dave Mussell http://www.re-energy.ca/docs/wind-turbine-cp.pdf" . These plans were inspired by the Picoturbine: link to manufacturer and link to PDF. We used 30 AWG...

We are looking to effectivley build a wind turbine to capture the wind and create energy. What would be the most effective and easisest way to construct the windmill? I would like to focus on the design of the blades themselves. What design of the blades would provide maximum support and...

Hello. Let me make something clear right away, I don't think perpetual motion is possible. However, whenever I look into wind-turbines/cars I find forums bashing some young person for asking why we don't strap a windmill to the top of our cars. Obviously that wouldn't be an efficient way...

How do i develop a wind turbine model for electricity generation.

Hello, I am designing a rig to measure the rolling moment of a model aircraft. The rig will have a settable yaw, pitch and roll, but only the rolling moment is to be measured. The model aircraft will be similar to an Airfix model. Approx dimensions: L221 x W152. I was just wondering if anyone...

Is there a formula for calculating heat loss due to wind (not wind chill temperature)?

Homework Statement Model a 1KW windturbine. Homework Equations in this link u will find the equation (its equation 2-3) for a fit for a cp(lambda,beta) curve. It has 6 coefficients. The coefficients given are particular to a 1.5 MW windturbine. Does anyone know where I can find any...

Hi, I am again toying with programming and simple flight movements and whilst researching I've read that the angle of attack is perpendicular to the relative wind or flow and NOT an aeroplane wing. But isn't relative flow always in the oppostive direction of the planes direction vector...

I have wondered lately about the amount of energy which interacts with the Earth's magnetic field. Further, to the extent not converted to light as with the auroras, what happens to it in the interaction? If the energy is significant, is it in any way absorbed, transferred or otherwise lead to...

Homework Statement You are on an airplane traveling due east at 110 m/s with respect to the air. The air is moving with a speed 43 m/s with respect to the ground at an angle of 30° west of due north. 1)What is the speed of the plane with respect to the ground? >>> I answered this question and...

hi!... Does anyone know the relationship (i mean formulas) relating to the incoming air velocity to the rpm of a wind turbine?..i need to have a design in the generator part and also the parameters of the propeller..thanks! best regards, :)

I came across a report entitled "Wind Farms Provide Negligible Useful Electricity" by Richard Courtney. You can google it its just available free on the internet. What I wanted to know, if anyone here works in the power grid industry, was it true or should it be taken with a pinch of salt...

Could a small ducted fan / wind turbine say 4 -5 inches in diameter placed in the wind stream of a car develop enough energy at freeway speeds ( or less ) to help charge the cars battery at a realistic level say 30 to 75 amps 12v? I am thinking along the line of a duct from the front grill area...

Ok not a great title, but let me try to explain the idea. Imagine that you have say a parachute attached to the top of a flag pole. In the center of the parachute a hole is cut and connected to a plastic tube that goes to the ground. When the wind comes up the parachute exerts a drag on the...

how do we find the natural frequency of a tower of a wind turbine if, say, the tower is circular hollow cross sectional shape (its not tapered or anything, just cylindrical all the way up). I think i know how to find it when we're ignoring its weight, but what is it when weretaking into account...

Physics tells us that air molecules would cause friction which in turn would make an object hotter. So why do I freeze my :smile::smile::smile: off in the cold when it starts getting windy (while I'm obviously not sweating).

Renewable Energy (RE) Sources are a hot topic, but careful study of the solutions thus far offered make realizing RE as more than a tiny percentage of demand unrealistic. I have been thinking on an idea for a very large scale wind generator that I think is a potential solution for many of the...