Calculation method of air volume, relationship between wind pressure and wind speed

Wind speed measurement generally uses anemometers. Common anemometers include cup anemometers, propeller anemometers, hot wire anemometers and acoustic anemometers. Anemometers can more accurately measure wind speed and air volume. =The results of wind speed and wind duct interception area. Therefore, when the interception area of ????the air duct is the same, the greater the wind speed, the higher the air volume.

The higher the air volume and wind speed, the greater the resistance the system encounters. The smaller the air volume and wind speed, the smaller the resistance. It is not an absolute value, but is affected by changes in the air volume and wind speed of the party class at that time. The wind pressure and air volume generated by the fan can be converted into each other, but the greater the resistance the fan encounters, the greater the air volume.

Formula: wp=0.5·ro·v?. Among them, wp is the wind pressure [kN/m?], ro is the air density [kg/m?], and v is the wind speed [m/s].

Derivation process:

Where wp is the wind pressure [kN/m?], ro is the air density [kg/m?], and v is the wind speed [m/s].

Since the relationship between air density (ro) and gravity (r) is r=ro·g, so ro=r/g, using the formula: wp=0.5·r·v?/g .

This formula is the standard wind pressure formula. Under standard conditions (air pressure is 1013 hPa, temperature is 15°C), the gravity is r=0.01225[kN/m?], and the latitude is 45°. Acceleration g=9.8[m/s?], we get: wp=0.5·ro·v?.

Extended information

Wind has both size and direction. Therefore, wind forecast includes wind speed and wind direction. The magnitude of wind speed is often expressed as wind level. The level of wind is determined based on how much the wind affects objects on the ground. Meteorologically, winds are generally divided into seventeen levels according to their strength.

In weather forecasts, we often hear terms such as "North wind level 4 to 5", and the wind force referred to at this time is the average wind force; for example, we hear "gust level 7" and the like. In terms of wind gust, it refers to the wind speed that changes from high to low, and the wind force at this time refers to the strong wind force.

In fact, in nature, the wind force sometimes exceeds level 12. For example, the wind force at the center of a strong typhoon or a tornado may be much stronger than level 12. However, strong winds above level 12 are relatively rare, and generally the level is not specified.

Highest record

Hurricane John was the third Category 5 hurricane on record in the Central Pacific and set a record for the highest wind speed in the area, reaching 280 kilometers per hour. Since 1994, only Hurricane Ioke has reached Category 5 status in the central Pacific. Like Gilma, it had lower pressure but slower winds than John.

When Typhoon Wendai crossed Hong Kong, its intensity was equivalent to a Category 2 typhoon in the U.S. National Hurricane Center's tropical cyclone classification. At that time, the average wind recorded in Victoria Harbor reached 133 kilometers per hour, with a maximum gust of 259 kilometers. / hour, and Tate's Cairn also recorded a gust speed of 284 kilometers per hour.

Typhoon Taipei is the strongest tropical cyclone recorded on Earth. The tropical cyclone with the highest wind speed currently is Typhoon Haiyan in the northwest Pacific in 2013, with an average wind speed of 315 kilometers per hour.

The fastest "normal" wind speed on the earth's surface reaches 372 kilometers/hour, which was recorded on April 12, 1934 at Mount Washington, New Hampshire, USA, but in May 1999 In a tornado in Oklahoma, the fastest wind speed measured by researchers reached 513 kilometers per hour.

Baidu Encyclopedia - Wind Speed

Baidu Encyclopedia - Wind Volume

Baidu Encyclopedia - Wind Pressure