presented by Umut Türker Open Channel Flow
What is open channel flow? Open channel flow is a flow which has a free surface and flows due to the gravitational effect
What is open channel flow? Open channel hydraulics, a subject of great importance to civil engineers, deals with flows having a free surface in channels constructed for water supply, irrigation, drainage, and hydroelectric power generation; in sewers, culverts, and tunnels flowing partially full; and in natural streams and rivers.
What is open channel flow? An open channel is a duct in which the liquid flows with a free surface. This is in contrast with pipe flow in which the liquid completely fills the pipe and flow under pressure.
What is open channel flow? The flow in a pipe takes place due to difference of pressure (pressure gradient), whereas in open channel it is due to the slope of the channel bed (i.e.; due to gravity)..
What is open channel flow? In pipe flow: The hydraulic gradient line (HGL) is the sum of the elevation and the pressure head (connecting the water surfaces in piezometers). The energy gradient line (EGL) is the sum of the HGL and velocity head. The amount of energy loss when the liquid flows from section 1 to section 2 is indicated by h L..
What is open channel flow?
What is open channel flow? In open channel flow : The hydraulic gradient line (HGL) corresponds to the water surface line (WSL); the free water surface is subjected to only atmospheric pressure which is commonly referred to as the zero pressure reference in hydraulic engineering practice.
What is open channel flow? In open channel flow : The energy gradient line (EGL) is the sum of the HGL and velocity head. The amount of energy loss when the liquid flows from section 1 to section 2 is indicated by h L. For uniform flow in an open channel, this drop in the EGL is equal to the drop in the channel bed..
What is open channel flow?
What is open channel flow? Based on their shape, an open channel can be prismatic or non-prismatic:.
What is open channel flow? Prismatic channels: a channel is said to be prismatic when the cross section is uniform and the bed slope is constant.
What is open channel flow? Non-prismatic channels: when either the cross section or the slope (or both) change, the channel is referred to as nonprismatic. It is obvious that only artificial channel can be prismatic.
What is open channel flow? The most common shapes of prismatic channels are rectangular, parabolic, triangular, trapezoidal and circular.
Types of open channels Canal Flume Chute Drop Culvert Open Flow Tunnel
What is Canal? Canal is a long and mild-sloped channel built in the ground Coachella canal, USA
What is Flume? Flume is a channel usually supported on or above the surface of the ground to carry water Box flume, California, 1916 USA
What is Chute? Chute is a channel having steep slope. Gilbbesjavri, Northern Finland
What is Drop? Drop is similar to chute, but the change in elevation is affected in a short distance East Boulder River, USA
What is Culvert? Culvert is a covered channel flowing partly full, which is installed to drain water through highway and railroad embankments. A road to home, Anywhere
What is Open flow tunnel? Open-Flow Tunnel is a comparatively long covered channel used to carry water through a hill or any obstruction on or in the ground. Urfa tunnels in Turkey, for Southern Anatolian Project, Diameter, 7.62-m Length, 2x26.4-km Discharge, 80-m 3 /sec
Classification of open surface flow Open Channel Flow can be classified according to the variation by TIME and SPACE Steady and unsteady flow occurs with respect to TIME variance Uniform and nonuniform flow occurs with respect to SPACE variance
Classification of open surface flow Variation in time: Steady flow, velocity and depth does not change with time Unsteady flow, velocity and depth change with time
Classification of open surface flow Variation in space: Uniform flow, velocity and depth same at each different cross-section Non-uniform flow, velocity and depth vary between cross-sections
Classification of open surface flow In steady flows, all the characteristics of flow are constant with time. In unsteady flows, there are variations with time
Classification of open surface flow In uniform flow, all characteristics of flow are same along the whole length of flow. velocity, V 1 = V 2 and flow area, A 1 = A 2 In uniform channel flow, water surface is parallel to channel bed.
Classification of open surface flow In non-uniform flow, characteristics of flow vary along the whole length of the channel. By non-uniform flow, we mean that the velocity varies at each section of the channel. In the non-uniform flow, the energy grade line is not parallel to the bed of the channel.
Classification of open surface flow Non-uniform flow can be caused by: Differences in depth of channel Differences in width of channel Differences in the nature of bed Differences in slope of channel and Obstruction in the direction of flow.