Contraction Scour Adjustment for Pressure Flow, t
ABSCOUR 10 introduces a new procedure for estimating the effect of pressure flow in increasing the extent of contraction scour:
- The contraction scour depth (y2) is computed using the standard ABSCOUR equations
- The pressure flow separation zone thickness (t) is computed using the method described in the FHWA Manual HEC-18, Fifth Edition, Section 6.10.
- The adjusted scour flow depth (y2)adj is computed as the sum of y2 and t
- The contraction scour depth (ys) is computed as (y2)adj -yo
- The value of (ys) is adjusted by the calibration/safety factor as appropriate