PARAM, PREFDB

Bulk Data Entry Used to activate dB and dB(A) output in H3D and PUNCH file formats for Fluid-Structure Coupled Frequency Response Analysis.

Parameter Values Description
PREFDB Real > 0.0

No default

 This parameter specifies the reference pressure value used to calculate the pressure level in decibels (dB) and A-weighted decibels (dB(A)).
The pressure level in decibels (dB) can be calculated using the following equation:(1)
P L d B = 20 log 10 P L P R E F D B MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiaadcfacaWGmb WaaSbaaSqaaiaadsgacaWGcbaabeaakiabg2da9iaaikdacaaIWaGa ciiBaiaac+gacaGGNbWaaSbaaSqaaiaaigdacaaIWaaabeaakmaabm aabaWaaSaaaeaadaabdaqaaiaadcfacaWGmbaacaGLhWUaayjcSdaa baGaamiuaiaadkfacaWGfbGaamOraiaadseacaWGcbaaaaGaayjkai aawMcaaaaa@4B9E@
Where,
P L d B MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiaadcfacaWGmb WaaSbaaSqaaiaadsgacaWGcbaabeaaaaa@396B@
Pressure level in decibels (dB)
P L MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaamaaemaabaGaam iuaiaadYeaaiaawEa7caGLiWoaaaa@3AB1@
Magnitude of the pressure from Coupled Fluid-Structure Frequency Response Analysis
P R E F D B MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiaadcfacaWGsb GaamyraiaadAeacaWGebGaamOqaaaa@3ABA@
Reference sound pressure value specified using this parameter
Note:
  • The pressure level in decibels (dB or dB(A)) is not output unless PARAM,PREFDB,<value> is specified.
  • If this parameter is specified without a value, then an error is issued.
  • In the PUNCH file, within the PRESSURE (dB, dBA) section, the first two values printed for each frequency are the pressure level output in dB and dB(A) formats. The remaining values of each frequency are set to 0.0 for formatting purposes.


Figure 1.