Dunkirk: Where History Happened. We visit 10 places connected with the remarkable evacuation of the British Expeditionary Force from northern France in 1940. This feature was first published in the April 2010 edition of BBC History Magazine. Tuesday 25th May 2010.
The seepage velocity is less than the actual flow rate of the liquid or gas in the pores because the fluid moves only through the portion of the cross-sectional area S that is occupied by the pores.
Velocity. Average Velocity. Definition. Velocity refers to the rate of change of distance with respect to time. It is a vector quantity, which means that it has both - a direction and a magnitude. Average velocity refers to the average total displacement over the time of travel. Formula. Velocity = displacement/time