CIV E 530 - OPEN-CHANNEL HYDRAULICS

SPRING 2007 - MIDTERM 2 - SOLUTION

PROBLEM 4: COMPARISON BETWEEN DIRECT AND STANDARD STEP METHODS

    1. i. Direct-step method is EASY.

      ii. Standard-step method is DIFFICULT.

    2. i. Direct-step method is restricted to a PRISMATIC (usually artificial) channel.

      ii. Standard-step method is used for ANY-SHAPE (usually natural) channel.

    3. i. Direct-step method ASSUMES FLOW DEPTH and calculates distance.

      ii. Standard-step method ASSUMES DISTANCE and calculates flow depth.

    4. i. Direct-step method uses CHANNEL LENGTH as dependent variable.

      ii. Standard-step method uses FLOW DEPTH as dependent variable.

    5. i. Direct-step method advances DIRECTLY.

      ii. Standard-step method advances BY ITERATION.

    6. i. In the direct-step method accuracy increases with A SMALLER DEPTH INCREMENT.

      ii. In the standard-step method accuracy increases with MORE CROSS SECTIONS.

    7. i. Direct-step method uses ONE TYPICAL cross section.

      ii. Standard-step method uses MANY DIFFERENT cross sections.

    8. i. Direct-step method has MINIMAL data needs.

      ii. Standard-step method has EXTENSIVE data needs.

    9. i. Direct-step method uses SPREAD SHEET.

      ii. Standard-step method uses HEC-RAS.

    10. i. In the direct-step method an answer is ALWAYS POSSIBLE

      ii. In the standard-step method an answer is SOMETIMES NOT POSSIBLE.

 
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