Wind Definition and 829 Threads

1. A weather balloon travels upward for 6 km while the wind blows it 10 km north and 8 km east. Approximately what is its final displacement from its intial position? I am not sure how to look at this. I know they are vectors which makes this a bit complicated and I know I have to use...

In my current experiment, I am using a wind tunnel to test laminar flow over airfoils of various designs and at various angles of attack. My current dilemma is in deciding how to construct the airfoils. I am looking for a method that is precise and realistic. (At this stage, I am not worried...

Homework Statement 1. A wind turbine with a swept diameter of 20m and an efficiency of extracting energy from the wind of 40% is subjected to an average wind speed of 10m/s. (a) How much power might the turbine produce? Please can some one point me to the right equation as everyone I...

http://www.msnbc.msn.com/id/30448774/ This story rocks! The dog, named Tinker Bell (you can't make this stuff up!), was blown away by a strong wind. She was eventually found...with help from a pet psychic. Nice.

Hi, I have been toying with the idea of producing electricity from the cross winds that build up in my house. Basically when I leave a window open one one side of my flat and open a window on the other the wind blows through the house very strong. I want to place a wind generator on one...

Could someone please give me an answer with a scientific explanation for: Would a stationary vehicle or the same vehicle moving straight, at speed be more likely to be flipped over onto its side/roll when exposed to a strong gust of wind blowing at its side ("approx. perpendicular to the...

Why does the wind blow off the ocean during the day at the beach, and off the land during the night?

Homework Statement assume that the rotation period of saturn at the equator, very deep in the atmosphere is 10 hrs. higher in the atmosphere, the equatorial winds blow west to east at 250 m/s. What would be the rotation period of this higher level in the atmosphere? also know - maximum...

I have been trying to find answers to this but have had no luck so far. I'm hoping these forums can help me out. I have some specs for an antenna and need to decipher what the wind loads mean. I have attached a picture below. Basically, what does the Fa, Fs, and M mean? Thank you in advance!

for a physics project i am designing a vertical wind tunnel made out of stovepipe and powered by a leaf blower. this experiment is designed to find the terminal velocity of different shapes. We already have a way to vary the wind speed, but what we don't have is an accurate way to measure this...

Homework Statement An airplane pilot sets a compass course due west and maintains an airspeed of 220 km/hr. After flying for .5 hr, she finds herself over a town 120 km west and 20 km south of her starting point. Find the wind velocity (magnitude and direction). Homework Equations...

Even though I’ve experienced the evidence firsthand I’ve never quite been able to totally accept that the treadmill and turntable tests accurately represent a cart being powered solely by wind (like many others). So I’ve built a circular wind tunnel to test DDWFTTW in a “real” wind and the cart...

It seems to me that an obvious source of dark matter (and possibly dark energy) might be the massive ejections of spent fuel from our sun in the form of the solar wind. If our sun regularly ejects spent fuel in the form of the solar wind, it follows that the same process must happen in billions...

Homework Statement A 2500kg car is traveling 35mph into a head wind gust of 28mph. The wind gust lessens to 16mph. How many seconds will it take for the car to reach velocity of 50mph assuming the force applied to the accelerator throughout remains unchanged?Homework Equations The Attempt at a...

For a school science project I am supposed to design an experimental process that utilizes the wind tunnel my school owns. I've built four small model towers out of wood - one a triangular prism, one a rectangular prism, one a cylinder, and one a pyramid - that all have the same height and base...

Homework Statement A moderate wind accelerates a pebble over a horizontal xy plane with a constant acceleration a = (6i + 7j)m/s^2 . At time t = 0, the velocity is (3i)m/s . What are the (a) magnitude and (b) angle of its velocity when it has been displaced by 12.0 m parallel to the x axis...

Mmmmmmmmmmmm yeah.... not everyday you get to use one of these. I'll post more pictures once we start running wind tunnel tests. I'm 6'4", each red blade is as tall as I am. http://img509.imageshack.us/img509/1333/pict0389.jpg http://img15.imageshack.us/img15/2746/pict0388v.jpg...

I've been searching the internet far and wide but cannot seem to the wind speed information I want. I need a graph or table of wind speed vs. time, where the time scale is very small, on the order of seconds. I did find one graph here...

Hi, I'm trying to build a vertical wind powered turbine system and I'm have trouble finding a small, cheap generator/alternator to use. Does anyone have any suggestions?

Hey guys, new user here. I had a question about a project I am working on with a professor. Unfortunately he does not have much experience with fluent but is a very intelligent and experienced person when it comes to the theory. So I am basically trying to develop a chart of the power...

On May 10-12 1999 it has been stated in a website that the Solar Wind Disappeared. It stated that 98% of the total solar wind stopped but the piciures of the the SOHO satellite looked normal. Is this true or a crackpot site? The polar borialis was said to be strange and a phenonema of...

For years I have been wondering why wind turbines are designed with very skinny blades (photo http://en.wikipedia.org/wiki/File:Turbine_aalborg.jpg ). Most of the available wind passes right through the circular "reach" of the device without touching the blades. Wouldn't it be more efficient if...

I have come unstuck in my coursework project, and cannot find any information/equations for the effects of shielding on wind loading in a structure (This is not an ordinary structure, it is an unsymmetrical sculpture made up of circular and Universal beams). So i would firstly like to find how...

Homework Statement A plane attains an airspeed of 620 km/hr. The plane sets out for a destination 1085 km to the north (a 0° course) but discovers that the plane must be headed 20° east of north to fly there directly. The plane arrives in 2.00 h. What is the wind speed? What is the direction...

I am trying to charge a battery using wind power! but i can't seem to find anything telling me how i can determine the power output coming from the generator, when all i know is the wind speed.. i know that the blades on the fan will have to be small but using the right gears with the high speed...

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...

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...