Wind direction refers to the direction in which the wind blows. For example, north wind means that air flows from northto south.
Wind direction is generally expressed in 8 directions. They are: north, northeast, east, southeast, south, southwest, west and northwest.
Wind is a natural phenomenon caused by air movement, which is caused by solar radiation heat. Sunlight shines on the surface of the earth, causing the surface temperature to rise. The air on the surface expands due to heat and becomes lighter and rises.
After the hot air rises, the low-temperature cold air flows in laterally. The rising air gradually cools and becomes heavier and falls. Because the higher surface temperature will heat the air and cause it to rise, this flow of air occurs. The wind blew.
Division method
Wind speed refers to the horizontal distance that air flows in unit time. According to the phenomenon caused by the wind on objects on the ground, the size of the wind is divided into 13 levels, called wind power levels, or wind levels for short.
The terms "east wind level 3" that people usually hear in weather forecasts refer to "Beaufort level". The "Beaufort Wind Scale" is a wind power level determined by the Englishman Francis Beaufort in 1805 based on the degree of wind's impact on ground (or sea surface) objects. It is divided into levels 0 to 17.
What is southeast wind, northwest wind, southwest wind, northeast wind, how the wind blows, from which direction to which direction
You can do an experiment , take 2 paper pinwheels and place them in front of the fan, one behind the other, to see if the one at the back will spin.
After the wind rotates a generator to generate electricity, the wind energy is converted into kinetic energy, and the wind energy is reduced. If there is a generator immediately behind it, the wind energy received will be reduced.
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Supplementary information:
1. As the poster said, if it is installed in a pipe, the windmill at the back will naturally rotate, because When the wind blows in from one end, it will inevitably blow out from the other end, because the pipe changes the direction of the wind, forcing the wind direction disrupted by the windmill to return to its original direction. But wind turbines are built in the wilderness, and the wind flows freely without a pipe to restrain it. The wind blows from one direction, and after passing the wind turbine, its direction is disrupted and its speed is reduced.
2. I don’t quite understand this question.
The wind turbine rotates slowly because the wind speed at that time is slow. The faster the wind speed, the faster the rotation speed. The wind does not just blow between the blades, because the direction of the blades is not parallel to the direction of the wind, but at a certain angle. The wind blows on the blades, causing them to rotate. During this process, the wind does work on the blades, and the kinetic energy of the wind is converted into the kinetic energy of the generator.
Let’s take an extreme example: the wind blows on the wall, the wall does not fall, the wind speed drops to zero, the wall collapsesaffected by external forces. If the wall collapses, the wind speed will not be zero, but the speed will slow down because work is done on the wall - the same thing as a generator.
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Additional 2:
1. As the poster said, the air entering the duct is continuous. Theoretically, the wind enters A uniform duct (same duct cross-section) and the instantaneous velocity leaving the duct should be the same because there is no loss of air volume. This should cause all fans to spin.
The condition we assume here is a cylindrical pipe with the same cross-section. Because the wind direction does not change, we draw the above conclusion. The original poster had previously assumed a small box with two opposite holes. If it is a square box (the kind with edges), it is difficult to say whether to open two holes on each opposite side. Because gas vortices will occur in the corners of the square box, we must also consider various changes in the gas inside the box. . . Very complicated. If you are interested, I suggest you read some books on fluid mechanics.
2. When the fan blades are stationary, the gap between them is indeed large; but once the fan blades rotate, the gap between them will become smaller. The faster the speed, the smaller the gap. For example, when an electric fan is working, can you see the gaps between its blades? ----cannot. But when you turn off the switch, the fan blades rotate slower and slower, and the gaps become more and more obvious.
So, when the blades of the wind turbine are stationary or rotate slowly, there will be breeze or air passing between the blades; when the wind speed increases and the blades rotate faster and faster, there will be no gaps. doubts.
(1) Southeast wind is the wind blowing from the southeast and the wind blowing northwest.
(2) Northwest wind, a meteorological term, northwest wind refers to the wind blowing from the northwest in a narrow sense. Broadly speaking, it can be considered as west wind or north wind.
(3) Southwest wind refers to the wind blowing from the southwest to the northeast at an altitude of 315 degrees.
(4) Northeast wind is the wind blowing from the northeast and blowing to the southwest.
Definition of wind direction:
Meteorologically, the direction in which the wind blows is determined as the direction of the wind. Therefore, the wind coming from the north is called north wind, and the wind coming from the south is called south wind. When weather stations forecast winds, when the wind direction swings left and right in a certain direction and is uncertain, the word "bias" is added, such as northerly wind. When the wind force is very low, the explanation is "the wind direction is uncertain".
According to observations, northerly winds (north wind, northeasterly wind, northwest wind) are common in North China, the Yangtze River Basin, southern China and coastal areas in winter, while southerly winds (souther wind, southeasterly wind) are common in summer. wind, southwesterly wind).