Quick Answer: Why Trapezoidal Section Is Most Economical?

What is the condition for maximum velocity in case of most economical circular section?

1] Condition for maximum velocity for circular section: The value of wetted area A, is given by equation.

Thus, for maximum velocity of flow, the depth of water in circular channel should be equal to 0.81 times the diameter of the channel..

Which is the best hydraulic section of the following open channel cross section?

The half-circle is the ideal shape of the best hydraulic section of open channels, but semicircular channels are not practical to construct. The semicircular section is approximated by a composite section that is composed of a trapezoidal section at the bottom and a rectangular section at the top.

What is the most economical section?

channel sectionA channel section is considered as the most economical or most efficient when it passes a maximum discharge for given cross section area, resistance coefficient, and bottom slope.

What are the geometric properties for the most efficient hydraulic section of a triangular channel?

The geometric properties of the best hydraulic round‐bottom triangular section are of great interest. Its depth is equal to the round‐bottom radius and is twice its hydraulic radius.

What is hydraulic jump in fluid mechanics?

A hydraulic jump is a fluid shockwave created at the transition between laminar and turbulent flow. … Friction against the sink surface slows the flow until an abrupt change occurs. At this point, the depth increases as water piles up in the transition region and flow becomes turbulent [1].

What is hydraulic radius of channel section?

Hydraulic radius, abbreviated as rh, is the area cross-section of water in a pipe or channel divided by the wetting perimeter.

Which hydraulic jump occurs in our sink?

In the image above, high-velocity water is flowing from a tap into a sink already filled with water. At first, the tap water spreads out quickly and smoothly, but as it loses energy it slows down and ‘piles up’ in a ring around the point of inflow. This ring is the hydraulic jump.

What is non prismatic channel?

PRISMATIC AND NON-PRISMATIC CHANNELS: ➢ A channel in which the cross sectional shape, size and the bottom slope are constant is termed as prismatic channel. ➢ All natural channels generally have varying cross section and consequently are non- prismatic.

How do you find the side slope of a trapezoidal channel?

Trapezoidal Cross Section The side slope is usually specified as horiz:vert = z:1. A = (y/2)(b + b + 2zy), because B = b + 2zy, as can be seen from the diagram.

What is the most economical section for a column?

Economical section for columnA. Hexagonal.Rectangular.Tubular section.Solid round.

What type of channel geometry is most efficient and why?

Maximum flow (water and sediment load) is only possible when the cross-sectional form attains the semi-circular or parabolic shape (Knighton 1998) or equilateral-triangular or rectangular (Hickin 2004) shape. These shapes generate the minimum turbulence and shear stress hence channel becomes the ‘most efficient’.

What is meant by an economical section of a channel?

A channel is said to be most economical if. It gives maximum discharge for a given cross -sectional area and bed shape, It has minimum wetted perimeter, and. It involves lesser excavation for the designed amount of discharge.

What is the best hydraulic section?

A channel section with a minimum wetted perimeter for a given flow area is termed the best hydraulic section. The best hydraulic section has the shape of a half-square for rectangular channels and a half-hexagon for trapezoidal channels (Jain 2001).

In which case is the hydraulic jump not possible?

Explanation: Hydraulic jump is not possible when the initial speed is less than the critical speed. There is a transition that is created during the change. Fluid flow after the hydraulic jump is typically rough and choppy turbulent flow.

Which is the condition for most economical rectangular cross section?

Explanation: If the wetted perimeter is minimum, amount of materials required for construction of the channel is less and hence the channel is more economical. 2. A rectangular channel section has depth y and width B, calculate the most economical area of the channel.