Fluid Mechanics - The study of fluids - liquids and gases.

Acoustics - Room acoustics and acoustic properties, decibel A, B and C, Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity and sound attenuation.

If the Mach Number is above 1, the flow velocity is higher than the speed of sound - and the speed is supersonic.

If theВ Mach Number is 1 - the speed is transonic.If the Mach Number is below 1, the flow velocity is lower than the speed of sound - and the speed is subsonic.Elastic Properties and Young Modulus for some Materials.Speed of Sound in Water - Speed of sound in water at different temperatures - imperial and SI units.The speed of sound in water at 0 oC can be calculated asД¬ = ((2.06 10 9 N/m 2) / (999.8 kg/m 3)) 1/2 = 343.1 (m/s) Example - Speed of Sound in Water The speed of sound in air at 20 oC (293.15 K) and absolute pressure 1 bar can be calculated as

The speed of sound in air at 0 oC (273.15 K) and absolute pressure 1 bar can be calculated as R = individual gas constant (J/kg K, ft lb/slug oR)ДЇor an ideal gas the speed of sound is proportional to the square root of the absolute temperature. K = ratio of specific heats (adiabatic index) For an isentropic process the ideal gas law can be used and the speed of sound can be expressed as Since the acoustic disturbance introduced in a point is very small the heat transfer can be neglected and for gases assumed isentropic. Speed of Sound - Sonic Velocity - in Ideal Gases If a medium is not compressible at all - incompressible - the speed of sound is infinite ( c в‰€ в€ћ). The sound travels faster through media with higher elasticity and/or lower density. This equation is valid for liquids, solids and gases. The acoustic velocity can alternatively be expressed with Hook's Law as The acoustic velocity is related to the change in pressure and density of the substance and can be expressed asДПЃ = change in density (kg/m 3, lb/ft 3) Speed of Sound in Gases, Fluids and Solids Velocity is vector quantity with direction. The velocity at which a small disturbance will propagate through the medium is called Acoustic Velocity or Speed of Sound. A disturbance introduced in some point of a substance - solid or fluid - will propagate through the substance as a wave with a finite velocity.

Soundation velocity