the loss of head due to sudden expansion of a pipe is due to
Hi Aman,
The loss of head due to sudden expansion of a pipe is due to sudden enlargement. Sudden enlargement in the pipe diameter results in the formation of eddies in the flow at the corners of the enlarged pipe. This results in the loss of head across the whole fitting.
Feel free to ask doubts in the Comment Section.
I hope this information helps you.
Good Luck!




