Wind table level and wind speed
wind rating and wind speed table
wind scale: says wind of a method, usually adopts the beaufort scale. The wind usually use of wind direction and wind speed Wind and the wind scale) To represent. Wind speed is refers to the air flow in unit time mobile distance, from rice/SEC or km/hour.
the British PuFuPing according to the wind on the ground (1805 Or the sea) Objects to the level of influence degree, from 0 12, a total of 13 level, said PuShi takes place. Since 1946, the level of wind made some changes, to 18. The Chinese mainland is still used to use 12 level.
wind pressure is perpendicular to the plane of the airflow direction of the wind pressure. According to Bernoulli equation of the wind - Pressure, wind pressure for wp = 0. 5• ro• v ( 1)
the wp for wind pressure [ kN / m2) As his air density, ro kg/m3] As his speed, v m/s] 。
due to air density ( ro) And severe ( r) The relationship between r = ro• G, hence the ro = r/g. In the ( 1) Using this relationship, to get wp = 0. 5• r• v / g ( 2)
this type for the standard air pressure formula. In the standard state ( Air pressure is 1013 hPa, temperature of 15 & deg; C) , the air is heavy r = 0. 01225 [ KN/m 砞. Latitude 45 & deg; The acceleration of gravity g = 9. 8 [ m/s] We get wp = v / 1600 ( 3)
this type for the general formula of wind pressure with wind speed estimation. Should be pointed out that, the air is heavy and the acceleration of gravity change with latitude and altitude. Generally speaking, the r/g in plateau than in the plain area is small, that is to say the same wind speed at the same temperature, the wind pressure on the plateau of smaller than in the plain area.
now we will wind generation into the ( 3) , 10 class gale is equivalent to 24. 5 - 28. 4 m/s, take 28 wind speed limit. 4 m/s, wind pressure wp = 0. 5 [ kN / m2) , which is equivalent to a billboard under 51 kilogram per square metre.
wind is the wind to the size of the object of power. General according to the wind to the ground or surface of an object produced by a variety of phenomena, the wind was divided into 13 levels, the size of the minimum level is zero, the maximum is grade 12.
wind scale _ wind speed table in its possession:
level 0, no wind is calm, smoke washed up. Level 1 light air, smoke in the direction, inclined to the sky.
2 levels of light, people have a feeling, the leaves micro. Level 3 breeze, leaves shake, flag in the wind.
4 and wind, dust, paper wind to send. Level 5 wind, pond water wave, small shaking.
6 levels of winds, for umbrella difficult, wires buzzing. Tough level 7 high wind, the wind, trees bow.
8 gale, broken branches, river's lake wave. The magnitude 9 gale damaged roofs, blow ruined chimney.
in addition, according to the need of wind can be converted to the corresponding wind speed, which is the distance of the air flow per unit time, use metres per second, said its conversion formula for reference: pull to one, add a level 3 three. Four to nine grade is easy to calculate, cut square three series. Ten to twelve, keep in mind the ten steps it is good to do. 27 tenth level wind speed, each with more than four to one.
the level of the wind speed is equal to 1 m/s wind, light breeze of wind speed is equal to 2 m/s. Breeze wind scale and add 1, the wind speed is equal to 4 m/s. Grade four to nine in the series minus 2 takes 3, get the corresponding level of wind speed. Ten to ten secondary wind speed of the algorithm is the same, ten level wind speed is 27 meters/seconds, on the basis of add 4 to 10 level of 31 m/s wind speed, add 4 to 10 secondary 35 m/s wind speed.
level phenomenon of m/s
1 can smoke said the wind. 0. 3 to 1. 5
2 people feel there is wind, the leaves micro. 1. 6 to 3. 3
3 leaves, sway and micro technology standard. 3. 4 ~ 5. 4
4 can blowing dust and paper, ground shaking the small branches. 5. 5 to 7. 9
5 leaves swaying trees, inland water with wavelet. 8. 0 a 10. 7
6 big boughs, wire whirring sound, difficult for umbrella. 10. 8 to 13. 8
7 full tree, the wind walk feel inconvenience. 13. 9 ~ 17. L
8 branches damaged, forward line feeling very large resistance. 17. 2 ~ 20. 7
9 the destruction of a straw bough can be broken. 20. 8 ~ 24. 4
10 trees blown over, and the general building destruction. 24. 5 ~ 28. 4
11 rare of the land, the tree can be blown over, general buildings were badly damaged. 28. 5 ~ 32. 6
12 land rarely, its devastated force greatly. 32. 7 ~ 36. 9