Briefly describe wake turbulence and wind shear?

Answer 1

I strongly suggest you get your self a copy of the FAR/AIM
all of the information you are asking here is in it.
Chapter 7, section 3 gives a very good synopsis.

You will find the FAA Pilot's Handbook of Aeronautical Knowledge very helpful as well,
http://www.faa.gov/pilots/training/handbook/

Answer 2

Wake turbulence is a disturbance of the air caused by the passage of an aircraft through that air. In the same manner as passing an 18-wheeler in your light car will cause you to have to correct with your steering wheel, one aircraft passing through where another has just been flying will cause you to feel turbulence. Pilots performing in-flight refueling experience this as a rough spot just before passing into the zone for refueling. Wind shear is usually a vertical flow of high-speed wind, most often caused by thunderstorms. One column of air will be rising at 1 or 2 hundred mph while immediately beside that will be a column descending at a like velocity. Any aircraft passing through those has got a problem, often in the form of wings being pulled off as those who fly into thunderstorms unprepared find out, the hard way. You can also have a lesser wind shear off the end of some runways due to terrain, usually a ditch or some such. These are nowhere near as violent.

Answer 3

Wake turbulence are like mini tornadoes that are produced off the wingtips of an airfoil that is producing a high amount of lift.The airflow over the top of the wingtip's trailing edge slips downward and twists as it meets back up with the slower airflow under the wing.This is much like the wake produced by boats.Wake turbulence is VERY important near large airports with large heavy aircraft as W.T.takes sometime to diminish as they spin downward and out.Smaller aircraft are highly effected and should NOT take W.T.lightly.Been there,done that! Wind shear is a virtical colume of air that is in motion upwards or downwads.It can be formed by ground conditions,mountains or a vairiety of weather conditions,thunderstorms with alot of convection.C.A.T. or clear air turbulence is just that. A rough ride on a clear day.

Answer 4

Ah, something I have to deal with when I fly my hang glider. Wake turbulence is the disturbance of the air caused by a wing or other object moving through it, much like a river with a big rock in the middle of it causes whorls and eddies behind and in front of the rock as the water is disturbed.

Shear is when two masses of air moving in different directions and different speeds come together. When I fly at a coastal site like Fort Funston, California, normally I can get about 400 feet higher than the cliff edge from the prevailing westerly winds providing lift as they strike the cliff face. When a shear condition sets up, I can get up to 2,100 feet above that same cliff.

Answer 5

Wake turbulence is the disturbed air that results from an aircraft having moved through that area. There are videos showing the wake turbulence being formed off the wingtips of aircraft.
Wind shear is force of air that thrusts an aircaft down causing a loss of altitude rather quickly

Answer 6

I would just add to Ray KC's excellent description above. The upward and downward velocities mentioned with respect to windshear might sound awkward at first. This is how it happens, the column of air falling down hits the ground and mushrooms outwards. The rebounding air will travel upwards and might be a couple of hundred meters to a km or more in width. So the windshear is a tricky situation and penetrating the shear through the center will cause you to encounter the following:
1) A transition from clear air (or near clear) to an updraft that is part of the near rim of the mushroom.
2) A violent transition from the updraft to the downdraft of the falling column, velocity gradient may exceed 100 knots.
3) Another violent transition from down draft to updraft as you approach the far rim of the mushroom.
4) A final transition from the updraft to the clean air outside the shear.

Picture a mushroom sliced down the vertical and you can imagine how bumpy the ride would be. The most dangerous aspect of this is that windhears occur near ground and a drastic change in altitudes near ground would be disastrous.

Answer 7

Wake turbulence is caused by moving through airspace that another aircraft just moved through. The airflow across control surfaces and air intakes will not be laminar. This will result in buffeting and probable loss of thrust.

Wind shear is a natural phenomenon; it's a lateral crosswind typically in the opposite direction that you are currently compensating for.

Either of these conditions, if severe enough, can ruin your day.

Answer 8

Wake turbulence is caused by wingtip vortices and jet and prop blast. Wingtip vortices form whenever lift is generated and are the result of high pressure air below a wing spilling over the wingtip. Greatest wingtip vortex danger is produced by large, heavy aircraft that are operating at low speeds, high angles of attack, and are in a clean configuration.

Wind shear is a sudden, drastic shift in wind speed and/or direction that can occur at any altitude in a vertical or horizontal plane.

Answer 9

WIND SHEAR is a change in wind direction and/or speed with height over a very short distance. We can think of wind shear as a gradient in wind velocity that can be interpreted in the same way as a pressure or temperature gradient.

TURBULENCE - Any irregular or disturbed flow in the atmosphere. In aviation, it refers to bumpines in flight.