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sdways01
11-18-2009, 01:38 PM
Monday while on the top of Mt. Moosilauke in the windy conditions, I was thinking about what factors affect wind speed on the summit of a mountain.

Does the shape of the mountain make a difference? Does it act like an airplane wing speeding up the wind as it goes over? Is is partially dependent on the elevation you are at? Does wind just go faster up high? Or is it more the shape of the surroundings funneling the air properly to increase the speed?

TrishandAlex
11-18-2009, 07:11 PM
Great question! Looking forward to the responses.

Bill O
11-18-2009, 09:34 PM
Does the shape of the mountain make a difference?

Yes. Smooth mountains have less friction and constricting valleys help to funnel the winds.

Does it act like an airplane wing speeding up the wind as it goes over?

A little over-simplified, but yes. It has more to do with the air squeezing between the mountain and a stable airmass above.

Is is partially dependent on the elevation you are at? Does wind just go faster up high?

Wind speeds increase with elevation (think jet stream) due to less friction. Taller mountains protrude higher into the free atmosphere.

Or is it more the shape of the surroundings funneling the air properly to increase the speed?

See above, the shape helps.

In short, mountains have a lot going for them in terms of having high wind speeds. Mount Washington in particular has even more. Smooth slopes, its' higher than all the other peaks, the valleys funnel winds up its slopes, it gets a lot of storms....

jonebay
12-17-2009, 07:07 AM
That is innaccurate.The sound speed, at moderate velocities of wind, is almost constant throughout the flow field.That is, velocities of wind such as 10 m/s does not produce a substantial variation of the speed of sound compared with that in still air. What makes the desired sound more difficult to be heard is the interference with the rest of pressure waves in your ears produced by wind fluctuations as you said in a windy day. Another point is that the sound wave can be carried faster if the wind is faster, because the sound wave is advected by the fluid.Maybe true that wind slows deer movement down, but I believe the big boys are more likely to be in the open during windy days. Nothing scientific to back it up, but my only two big bucks were killed in open fields on 15-25 mph days.I have noticed a large decrease in the total number of deer seen,just not bigger deer. Maybe just chance, but I'm heading to a field on a windy day.Thanks.

Brad
12-17-2009, 04:55 PM
That is innaccurate.The sound speed, at moderate velocities of wind, is almost constant throughout the flow field.That is, velocities of wind such as 10 m/s does not produce a substantial variation of the speed of sound compared with that in still air. What makes the desired sound more difficult to be heard is the interference with the rest of pressure waves in your ears produced by wind fluctuations as you said in a windy day. Another point is that the sound wave can be carried faster if the wind is faster, because the sound wave is advected by the fluid.Maybe true that wind slows deer movement down, but I believe the big boys are more likely to be in the open during windy days. Nothing scientific to back it up, but my only two big bucks were killed in open fields on 15-25 mph days.I have noticed a large decrease in the total number of deer seen,just not bigger deer. Maybe just chance, but I'm heading to a field on a windy day.Thanks.
I am not a weather guy - just trying to understand. How does this relate to the question of wind speed?

Snow Miser
12-17-2009, 07:06 PM
Ya, I confused too.:confused:

Bill O
12-17-2009, 07:48 PM
Spammer. Thinking about a course of action.