Question

What is the total wetted area of a trapezoidal section of depth y base B and side slope Z?

(a) Z(B+Zy)

(b) y(B+Zy)

(c) Zy^2

(d) Zy

This question was posed to me by my college director while I was bunking the class.

I want to ask this question from Geometrical Properties of Trapezoidal Section topic in section Flow in Open Channels of Fluid Mechanics

Answer 1

Right answer is (b) y(B+Zy)

To explain: Total Wetted Area = 2(Area of triangle) + (Area of rectangle)

A = 2(^1⁄2 Zy)(y) + (By)

A = Zy^2 + By

A = y(Zy + B).