Wind Definition and 861 Threads

Homework Statement A 54 kg skier skis directly down a frictionless slope angled at 12° to the horizontal. Choose the positive direction of the x-axis to be downhill along the slope. A wind force with component Fx acts on the skier. What is Fx if the magnitude of the skier's velocity is (a)...

Hello everyone, I would just like to know these few things, since I'm trying to build my own little variation of a wind tunnel for my experiment with sound. 1. How is the velocity of the wind inside the tunnel measured? 2. Following the first question, how then would I go about...

This isn't really a homework problem, but I am doing a research paper on the topic 'the Speed of sound in different air velocities'. I was just wondering is this is an appropriate topic, and whether or not I would be able to research and collect enough data for a 4000 word essay. Any...

Hey, got a bit of a problem; got a few questions on wind Shear in Dams & retaining walls. Can anyody help http://img296.imageshack.us/img296/9366/image0003xb2.jpg Thanks Andy.

(I'm not sure if I posted this topic in the appropriate category. The project I'm discussing is for my school, but seems bigger and different than a homework question. If it's not the right section I'm sorry) I want to measure the relationship between various aspects of wind generated waves...

1. Homework Statement Air at 20 degrees celsius and 100kpa is drawn into a wind tunnel. If the deflection h of a water manometer that is connected to a hole in the wall of the test section to measure the gauge pressure in the flow is 98mm. Calculate air speed in test section in m/s ignore...

Homework Statement Air at 20 degrees celsius and 100kpa is drawn into a wind tunnel. If the deflection h of a water manometer that is connected to a hole in the wall of the test section to measure the gauge pressure in the flow is 98mm. Calculate air speed in test section in m/s ignore fluid...

If supposing we were to add a wind turbine connected to a generator to a moving car, would we be able to get the air flowing around the car to turn the turbine and therefore gain some energy? If it is possible, is it economical? if it is, is it practical? would there be a loss? would there be...

Having a little bit of trouble with this and not sure if my findings\thoughts are right and would like some insight. If a boat is traveling south at 10 km/h and a person on the deck measures the wind velocity to be 8 km/h east, would the actual wind velocity (velocity of wind relative to the...

Homework Statement I am working on making a small wind tunnel using a 20" fan. What i want to figure out is the force generated by the movement of air. I want to make the size of the tunnel shrink to help induce more velocity in the air (see picture). Homework Equations Bernoulli's...

POWER FROM A CONVECTION LOOP: this is a scaled down version of the solar tower updraft system planned for austrailia, or the SHPEGS project with water/silica jell adsorption instead of ammonia absorption, or the water spray downdraft 'culvert on a hillside', proposed for hot dry...

I need to test a model rocket which will have average airspeeds around 200 mph. I am hoping to construct a plexiglass box about 9 feet long, 3 feet wide and 3 feet tall. For these dimensions and airspeed requirements it looks like I'd need a 160000 cfm blower. Is this something I can feasibly...

I am trying to build a low speed wind tunnel, and have a question. I understand that the contraction cone speeds up the air (proportional to the area ratio). What I am confused on is how does this "mechanical advantage" factor into sizing my fan / motor? I am planning on a tunnel with a...

Homework Statement A sailboat is traveling east at 4.5ms-1. a suddent gust of wind gives the boat an acceleration a = 0.70 ms-2, 40 degress north to east. what are the boat's speed and direction 6s later when the gust subsides? Homework Equations V(@6s) = V(init.) + at The Attempt at a...

Homework Statement "Wind (density=1.29kgm^-3) blows over a flat roofed building of height 20m at 12ms^-1.The area of he roof is 100m^2.What is the magnitude and direction of the force exerted on the roof if the pressure difference between inside and outside is due solely to the fact that the...

Is there enough power coming from solar wind to some how collect and store as energy.

sir i am tying to make a wind electricity generator, but i am confused about selection of material that i have to use for the project. can hysterisis loop help me? how? what the graph will show to me? please explain. the use of steal magnet will make my generator light and more efficient or...

Why is it that air going at a high rate of speed always cold? For example, fans throws air at high speed and it's cold and when we, human blow air fast is always cold. WHY?

Hello, Is there people amongst you who have ever dealt with Wind Tunnel testing? I cannot find a special section for experiments in this forum... I have a few topic to launch! Thanks...

I'm doing an experiment (at A-Level) to see the efficiency of a wind turbine. I'm doing this by changing the number of blades and varying the wind speeds. I wondered if anyone had an equation that could look at efficiency? I have the current and the voltage (and wind speed). Sorry if I've...

Homework Statement A factory whistle emits sound of frequency f. On a day when the wind velocity is w from the north, what frequency will observers hear who are located, at rest, (a) due north, (b) due south, (c) due east, and (d) due west, of the whistle? What frequency is heard by a cyclist...

Hello, I am trying to work with an equation I have for force from wind on an enclosed building. The equation is two parts, consisting of Qz which relates the the gound structure to the building qz = CONSTANT * CONSTANT * CONSTANT * CONSTANT * V^2 * CONSTANT V being the velocity You then...

Homework Statement An airplane is flying at [80.0, 50.0(degrees)] m/s when there is no wind. Then the wind begind to blow at [18.0, -20 (degrees)] m/s. a) if the pilot does not change the heading of the plane what will be the resultant velocity over the ground? b) In order to maintain...

Homework Statement A sheet of aluminum of thickness .01 m lies in a parking lot. A wind blows over the top of the sheet. What is the minimum velocity that will cause the sheet to begin to rise: Assume the density of air is 1.18 kg/m^3 and aluminum is 2700 kg/m^3. Homework Equations...

Homework Statement Is this true? the observed doppler shift for sound waves depends only on the relative motion of the source and the receiver. Homework Equations this is a concept-like question The Attempt at a Solution If no, doesn't mean, wind will affect the doppler effect?

Hello, I have a small 300W wind turbine (Aero4gen). I also have a weather station which datalog's the wind speed/direction, ect... at intervals of 5 mins also there is a solar radiation sensor (photodiode) (0 to 3 volts). Anyway, i will not be needing the solar radiation datalogging facility...

Hmm, i have this cenario, there is a cannon and it's target, separated by a distance d, not necessaraly in the same heigh. what i need is a function that gives the velocity needed for the cannon ball reaches the target. PS: consider the angle 45°, there is wind velocity, but not air...

I've been thinking about the wind turbine (horizontal turbine - like an airplane propellor.) that I pass on the way downtown and I'm realizing I've been taking for granted how it works. Seems to me it's exactly opposite of an airplane wing. Rather than forward speed generating lift, you have...

Homework Statement hello everyone, Im new to this forum but i really need some help doing a physics assignment. I am trying to use Newtons second law and the equation for wind resistance(click link) to determine the the angle made by a specific velocity. The link to the assignment is...

Hi Group, Just wanted to find out : The solar wind particles are electrically charged and arrive at the earth with great speed, then get trapped by the magnetic field in the magnetosphere envelope round the Earth. Right...:biggrin: Now, what about quantity? please can you guys...

Homework Statement The graph shows the speed as a function of time for a minivan, coasting on neutral along a straight, level road, loaded with windsurfing equipment and towing a boat. The total mass is 2500 kg, weight= 5512lbs. Find the size of the force due to wind and rolling friction when...

HI folks, new to this forum.I posted this on a different thread, but this seems the better location... it's a conceptual question. I'm in a Fluid Dynamics class and need to make a presentation on Bernoulli's conservation of energy equation as it applies to wind turbines. I think I...

HI folks, new to this forum. I'm in a Fluid Dynamics class and need to make a presentation on Bernoulli's conservation of energy equation as it applies to wind turbines. I think I understand the different energies involved here: kinetic(v^2/2), pressure(P/rho), potential(zg)... I want to...

Hi everyone…. I’m trying to evaluate the feasibility of putting what is essentially a wind turbine inside a horizontal exhaust shaft. I have a feeling that this would affect the volume flow rate through the shaft, but am having difficulty proving it. I have found plenty of textbook examples...

I am building a small wind tunnel, and I have a few questions about it. First: The Fan I am using produces 800cfm and is 12'' in diameter, I am going to narrow it down to 6''. The calculated wind speed that I got was 74.5km/h. Can anyone back me up on this? Second: When I use scale models...

I feel that this may be a silly question, but, Does wind affect how far sound can travel? I know that the air temperature affects how far a sound can travel (does wind affect air temperature?), but what about wind? I tried to find an answer via google, but I haven't found anything...

On my homework is says "On the Beaufort scale of wind force, the term "fresh gale" describes wind speeds from 39 mi/hr to 46 mi/hr. Write a compund inequality to describe "fresh gale" wind speeds." Would an acceptable inequality be {S: 39 < S < 46} ?

Does anyone have any good suggestions or design ideas. I have an idea in mind but outside input and help would be much appreciated. The site that has the project details is http://www.manchestertwp.org/teacher/mths/pwhite/Physics_files/physics%20oly%202006%202007/EVENT%205.mht .

Ok, doing a project at the moment and this is one of the issues I have to overcome; The information I have researched is as follows: If this is the case then a 88m diameter rotor should generate 2400kW? But the below diagram from the same page shows a 80m diameter rotor generates 2500kW...

convection right?

Do fish---- Break wind, when looking at them in aquariums i have never seen bubbles coming from that end, so may be their digestive system works differently.

The question said that the airplane turned west for 255km/h, and the resultant was 225km/h South 70 degrees West. I have to find the wind direction and velocity. How?

Is it possible that one day, the Earth magnetic field get so weaken that solar wind could strip off water from earth? I ask this because of this article which leads me to draw the parallel. http://www.geotimes.org/sept04/NN_solarstorms.html

Recreating the Mythbusters' Terminal Velocity Wind Tunnel - Need advice on Manometer Hello, I am trying to find the terminal velocity of a projectile. I am placing the projectile inside a clear tube and blowing compressed air inside the tube until the projectile is hovering at some height...

Suppose the force of wind resistance is proportional to the speed of the object and in the direction opposite of the object’s velocity. If you throw an object upward, when is the magnitude of the acceleration the highest? a.It is highest at the top of its trajectory. b.It is the highest...

Relative velocity question -- plane and wind The distance between two cities A and B is l. An airplane travels back and forth between A and B, flying in a line, with velocity V relative to the air. (a) Find the total flight time, if the wind blows with velocity v, in a direction that forms an...

I can create/solve the math problem without any difficulties once I have diagram in place, but I am having trouble setting up the diagram so that I can visualize it. The questions is: A novice pilot sets a plane's controls, thinking the plane will fly at 2.50 x10^2 km/h to the north. If the...

Is there a (freeware?) program to calculate 3D lift and drag for simple flying bodies, e.g. ball, cylinder, cube, wing? There are programs to calculate lift and drag for foils (2D programs), e.g. javafoil of Martin Hepperle. Those programs could be used to study the flow in 2D only. E.g...

I wonder if anyone could shed some light or information about the subject I'm looking into. How will wind turbines with varied amounts of blades perform in varied wind speeds. E.g. the less amount of blades you have the better a turbine will perform at higher wind speeds? Any help on the...

Hello all, My boss wants me to create a form of short term wind prediction based off a collection of long term wind data. I haven't taken a course in statistics so this is totally new to me. Basically, the data is organized by Year > Month > Day > Hour > Wind Speed with data stretching back...