Pipeline Engineering

Vortex Induced Vibrations (VIV) Analysis

This tool can be used for calculating the maximum allowable free span length (MAFSL) of exposed steel pipelines at water crossings or during flood conditions based on fatigue limit from vortex shedding. Vortex Induced Vibrations (VIV) Analysis equations can be found in "Analysis and Accessment of Unsupported Subsea Pipeline Spans", published by United States Deparment of The Interior Minerals Management Service.

Data Inputs

Select "Custom" for manual pipe OD and wall thickness inputs.
inch
inch
inch
Tip: Enter 0 for pipe without concrete coating weight
lb/ft³
Tip: Enter 0 for empty pipe
lb/ft³
lb/ft³
lb/ft³
psi
 
The free span end fixity constant, Cf is generally taken as 1.5 for simply support ends and 3.5 for fully fixed ends. In an actual pipeline, free span end fixity will be neither purely simple nor purely fixed supported. Rather, the free span ends will be partially fixed. An end fixity constant Cf should be selected between these two values in order to approximate actual free span conditions.
 

Results

VIV MAFSL