HEC-22 Energy (Third Edition) - Benching

One component of Total Additional Structure Losses ( $H_{A}$ ) is the energy loss due to benching.

Similar to the consideration for benching within the Second Edition method, the structure's benching classification equates to a coefficient used to derive the component loss. However, the benching coefficient in Third Edition protocol is a factor applied to relative Entrance Loss instead of a minor loss coefficient applied to the velocity head.

H_{B} = C_{B} E_{a}

$C_{B}$ = HEC-22 (Third Edition) Benching Coefficient.

$E_{a}$ = Relative Entrance Loss (See also: HEC-22 Third Edition - Entrance Loss.

The Third Edition of HEC-22 Manual categorizes five distinct for benching configurations.

Within the calculation option a Bentley user may customize the value of the (

C_{B}

) coefficient which maps to each benching configuration. The default (

C_{B}

) values are those recommended by Table 7-6 within the HEC-22 manual. For further flexibility, separate (

C_{B}

) values may be provided by the user for submerged and unsubmerged conditions. (See also: Calculation Options.)

Note: Between submerged and unsubmerged conditions, the applicable (

C_{B}

) coefficient will be interpolated between these two values for the corresponding benching configuration.