Question

Gradually varied flow is______.

• A. Steady non-uniform flow
• B. Steady uniform flow
• C. Unsteady uniform flow
• D. Unsteady non-uniform flow

Answer 1

The correct option is A Steady non-uniform flow

• GVSF = Gradually varied steady flow for backwater curve due to any obstruction.
• GVUF = Gradually varied unsteady flow. For flood flow in a river.
• RVSF = Rapidly varied steady flow for hydraulic jump
• RVUF = Rapidly varied unsteady flow for surges
• SVSF Spatially varied steady flow over a side weir
• SVUF Spatially varied unsteady flow for surface runoff or overland flow due to rainfall.

• Note:
  (i) It may be noted that in spatially varied flow some water is either added to the system or subtracted from the system. Whereas in GVF and RVF water remains unchanged.
  
  (ii) If the flow is uniform then it is always steady and if the flow is non-uniform, it can be steady or unsteady. It means unsteady & uniform flow is not possible.
  
  (iii) Steady and unsteady: If all the flow parameters such as depth of flow, velocity, and discharge are constant with respect to time at a particular section then flow is steady otherwise unsteady.
  
  (iv) Uniform and Non-uniform flow: if all the flow parameters are constant along the length then flow is uniform otherwise non-uniform.