Wind Definition and 861 Threads

The solar wind is a thin, hot gas given off by the sun. Charged particles in this gas enter the magnetic field of the Earth and can experience a magnetic force. Suppose a charged particle traveling with a speed of 8.20 106 m/s encounters the Earth's magnetic field at an altitude where the field...

http://news.bbc.co.uk/1/hi/england/lincolnshire/7817378.stm Any thoughts?

Homework Statement A plane flies 500km from Toronto to Montreal in 2.5h. The return trip takes 3.0h. Assuming the plane flew under constant power, determine: Homework Equations a) The speed of the plane in still air Well that's easy. b) The speed of the wind. Express your answer...

Homework Statement I'm trying to solve a problem related to the solar wind pressure at Jupiter but I'm stuck at calculating the density. It is stated that the solar wind has a density of 5 [itex]cm^{-3}[/tex] and a speed of 400 km/s at the orbit of the Earth, and that it should be assumed...

Hi Folks- Is there a way to determine the air pressure caused by wind at a given mph on a human being? Thanks! MD

Recently I read a research about Polar wins saying that million of kilos of our atmosphere (Hydrogen, Helium and Oxygen) left the planet via North Pole. May be possible to build a hot hydrogen balloon to leave the planet via North Polo Win??

We got hammered by a storm last night. Given the number of very large trees on the property, we always worry when we start getting gusts of 50mph and greater. My brother just called to say that his mother-in-law lost her home in the storm. His sister-in-law happened to be spending the night...

Hello! I chose an aspect of a dynamical system exhibiting resonance to model. The focus of the project is on the resonant response of the system. If the wind has a frequency that matches the natural frequency of a turbine, then the turbine will resonate due to wind. I am working on modelling...

What exactly is the wind chill factor? Do conventional mercury thermometers measure the wind chill factor?

There are a lot of discussions on other forums (like in this one: http://www.boatdesign.net/forums/boat-design/wind-powered-sail-less-boat-24669.html, but there are a whole lot more) about sailing direct downwind faster than the wind (direct downwind, not sailing at an angle, of course). There's...

I am considering the idea of making a small scale wind turbine for my final year B.Tech project. I have run into a roadblock, I have to maintain the generator at a relatively constant speed. I was thinking of 2 parallel shafts one from the Turbine blades coupled via a CVT to the shaft to the...

When a 20 mph summer wind blows past my window I don't hear anything. When a 20 mph cold winter wind blows past my window I hear whistles and howls and moans. Is there an easy explanation for this? nantz

Homework Statement I'm working on a project and my physics is a bit weak as I haven't done physics since High School and I needed to figure out wind resistance when traveling in a car at various speeds. For example: If you are traveling down the Interstate at 65mph, how much wind resistance...

Homework Statement (a) The wind-up radio is a wonderful example of the process of energy transformation from one type to another. The radio is operated as follows: (i) The user turns a handle that winds a metal spring onto a spool. (ii) The metal spring then unwinds slowly, through a...

was changed to a new thread... https://www.physicsforums.com/showthread.php?t=277401 thanks

The solar wind is a stream of charged particles plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. These particles are able to escape the sun's “gravity”, in part because of the high temperature of the corona..so i have...

Previous threads on the subject have gone badly and/or have moved quickly and gone round in circles without really getting anywhere. The question is whether a cart with a propeller powered by the wheels (or vice versa) can move downwind faster than the wind. It has (supposedly) been...

I've been following this on another forum and am planning to build a non-propeller design to sidestep the sailing references. I accept that the vehicles in the videos linked in the other two threads presented on this forum are doing what it looks like they are doing without any trickery. I also...

i'm currently building a wind tunnel for year 11 physics and need help mounting the aerofoil. The wind tunnel is basic (just cardboard and is circular), and i need a way to mount the aerofoil inside. The mounting has to be sturdy so that the aerofoil can have an adjustable angle of attack and...

Not too long ago Topher started a thread asking: is it possible to construct a wind powered vehicle that goes directly downwind - faster than the wind - steady state? I claimed this could be done, and I posted vector diagrams showing exactly how. This earned me a number of responses similar...

The wind in a severe storm is blowing 30 ms perpendicularly to the wall of a large barn of area 80 m2. Calculate the pressure exerted on it, assuming that the air density is 1.3 kg m3. I am quite new to this unit so i really have no idea what to do. Any help apreciated!

Aerodynamics -- Wind tunnel I'm not sure if this goes under here since it's not actually homework but it's more of a general question for a paper I have to do, so if it's in the wrong place I apologize; simply tell me and I'll delete it or something. Okay well for my research paper I'm...

A wind tunnel model of an aircraft, representing only the rolling motion, is constructed using two small lifting surfaces mounted in the horizontal (i.e. x – y) plane symmetrically on an axi-symmetric body. The body houses a set of ball bearings, which permit the complete model to roll about...

Homework Statement Find the minimum wind speed for the windmill to pump water. The pump is connected to a gear at a point 0.16m from the center. The radius of this gear (Gear 1) is 0.2m and the gear which it interlocks with is 0.1m (Gear 2). They intersect each other perpendicular to one...

Hi, What is the best way to design the root region of a wind turbine blade (for a small model turbine: 0.7m diameter, Re ~ 10,000)? So far we've selected our airfoil and calculated the chord lengths (proprtional to 1/R) but can't find any mathematics on the root region. At what point should...

Please help: We know that static pressure is the pressure felt when moving with the fluid (air). So in real flight the Pitot-static tube is moving with the aircraft and gives static pressure X (lets call it X). BUT in a wind tunnel the Pitot static tube is fixed (i.e. not moving) and the...

As I'm sure we all know, that when you go sailing your fastest speed isn't directly downwind but when you are traveling at an angle to it. This allows sailboats and iceboats to go several times faster than the wind speed that is powering them. But how is it that a vehicle such as...

Homework Statement An airplane is traveling at 30 m/s and wishes to travel to a point 8000 m NE (45 degrees). If there is a constant 10m/s wind blowing west: A) In what direction must the pilot aim the plane in degrees? B) How long will the trip take? Homework Equations Basic...

Hello, I am Daniel from La Plata, Argentina and would like some help on a complex (for me) question. I am working with some friends on the development of an innovative wind turbine. We have built several prototypes with diameters of 0.5 m and 2 m. We have tested these prototypes on trucks with...

Description of method: The rotor's mass is constant so when it accelerates in a given wind, it does so with an acceleration = torque/mass. This acceleration will depend essentially on wind speed. If tests are carried out in the open with non-turbulent winds it is possible by using a tachometer...

can someone explain in simple terms what does 1mw wind turbine mean? how many houses can this power? if it is a 500w turbine, how many houses can this power?

I'm about to start a project in which I want to study the effects of making modifications to a wind turbine blade. I am going to be able to use various external flow modeling software our aerospace labs. I am a mechanical engineer and am used to using solidworks and I understand that that can be...

A light plane attains an airspeed of 470 km/h. The pilot sets out for a destination 800 km due north but discovers that the plane must be headed 17.0° east of due north to fly there directly. The plane arrives in 2.00 h. What were the (a) magnitude (in km/h) and (b) direction of the wind...

We honestly haven't gone over this in class and I have no idea why my prof wants us to do this question... so I'm given it a go and come up empty. NEED HELP! Homework Statement Calculate the maximum theoretical power from a wind turbine if the radius of the vane area is 18.1 m and the wind...

Resultant wind speed/direction... Hi, new here and am hoping this is in the correct forum and if so that someone can help with this little problem. Basically I would like to know if there is a "quick" way of calculating an average or resultant wind speed and direction given a selection of 5...

To stop it from blowing out. Should you just have a 2 inch plastic around where the flame is?

A sailboat is sailing due east at 5.40 mph. The wind appears to blow from the southwest at 13.4 mph. 1. What is the true wind speed? 2.What is the true wind direction? ( south of west). 3.What is the true wind speed if the wind appears to blow from the northeast at 13.4 mph? 4.What is the...

Friends, I have a solid (not mesh) parabolic dish mounted on a 2-axis tracking mechanism. This assembly is often mounted atop buildings or open scapes and is subject to direct and indirect wind loading. I am trying to recall my fluids and aero schooling but am not sure of some assumptions...

Hello, I'm working on a project in which I need to design and build a home-made wind tunnel, and then publish instructions on building and using such a wind tunnel. My design is intended for middle school and high school student research, so it is simple yet as aerodynamically sound as I can...

Hello experts! I'm from one of the university in Asia and I'm planning to create a small prototype of Vertical Wind Tunnel for education purpose for my university. I don't know from where I should start the project. This small prototype will not bigger than 10-15 inches for the diameter and I'm...

I'm not sure if this is the right place to ask, but would any of you have recommendations as to where I can get this online first or preferably second hand at its best price? Alternatively, do any of you have this book and you wouldn't mind selling? My country is plenty small and my whole...

HI i am looking some virtual windtunnel software that there i have to desgin a various nose cone and i have to find the shock wave formation at supersonic speed please some one help me to find the virtual windtunnel and CFD software regards Ryan

Or any specific requirments formulas that will help me on my way in building one please. Moderator's note: this thread is from 2008.

my aim is to lower the cut in speed of the horizontal turbines. I know wind speed has a brutal effect on turbine output, so I want to use horns to speed up air. I plan to put a horizontal axis turbine in the midle of the hexagon You see on the pic. Each side of the hexagon is like a...

i know climate science is pretty inaccurate at the moment and its difficult to predict the effects of lowering carbon emissions but just as an interesting topic i was wondering roughly how many lives each wind turbine will save? what i mean is how much carbon dioxide will be saved from the...

I have constructed a wind tunnel with approximately 15 x 15 in. cross-sectional area test section. Where can i get some ideas/plans to build a simple force balance that can measure lift and drag forces simultaneously? Currently I'm using a single-axis button load-cell setup to measure...

This years's grants have been announced. A total of 2.7 million was awarded. FQXi is set up to support investigation of foundational questions. Here is a sampling of the awards, chosen with a hefty componenent of randomness. Gives an idea of some of the kinds of things FQXi supports.Stephon...

As part of a wind turbine design project, I have come to selecting the most appropriate coil and permanent magnet configuration. The aim is to design a turbine capable of 3kW (max), and approximately 300rpm. It will use mechanical furling to regulate speed. So far, I have only seen...

Hi All, I am trying to calculate the rotational torque created on a shaft from a rotating blade from wind pressure but have little idea how to go about this? Eg: If i have a flat piece of solid material of say 1" square or 2.54cm square facing into the wind blowing at say 30mph or 60kmh...

So I'm using a wind tunnel to show the aerodynamics of a toy truck which scaled 1:64 in the real world. My question is that if i wanted to show that it was going at 64 kilometers per hour in the real world, do i have to set the wind tunnel so that it generates 1 kilometer per hour winds? I'm not...