# PARAM, ALPHA1FL

Bulk Data Entry Adds Rayleigh damping to viscous damping for fluid mesh.

Parameter Values Description
ALPHA1FL <Real>

Default = 0.0

PARAM, ALPHA1FL is used in frequency and transient response analysis.

If PARAM, ALPHA1FL and/or PARAM, ALPHA2FL are not equal to zero, then Rayleigh damping is added to the viscous damping. ALPHA1FL is the scale factor applied to the mass matrix and ALPHA2FL to the fluid stiffness matrix as in:

$\left[B\text{'}\right]=\left[B\right]+ALPHA1FL\cdot \left[M\right]+ALPHA2FL\cdot \left[K\right]$