Community Noise Criteria

airbus a400

There are a number of different community noise criteria measurements, some of which are described below: CNEL = Community Noise Equivalent Level This is used to characterize average sound levels over a 24-hour period, with weighting factors included for evening and nighttime sound levels. Leq values for the evening period (7:00 p.m. to 10:00 p.m.) … Read more

Fan Design

microclene fan

One of the most important considerations in fan design is that the fan must impart a uniform velocity over it′s entire area. There are several simple relationships between fan capacity, pressure, speed, and power, which are referred to as the fan laws. The first three fan laws are the most useful and are stated as … Read more

Aerodynamic Noise

aerodynamic noise

When we flow gas through a pipe or over a surface (fluid dynamics) we generate noise and sometimes vibration, this all falls under the title of aerodynamic noise. The noise that is produced can be extreme if there is a feedback system between the noise that is generated and the gas flow. However, even under … Read more