CE 2200 Chapter : Lect 14
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Energy equation: (cid:3) (cid:5) (cid:4) (cid:4) (cid:4) (cid:4) (cid:2) (cid:3) (cid:4) (cid:2) (cid:2) (cid:1) (cid:1) (cid:11)(cid:5)(cid:12)(cid:11) (cid:3) (cid:2) (cid:5) (cid:4) (cid:2) (cid:2) (cid:2) (cid:3) (cid:2) (cid:2) (cid:2) (cid:1) (cid:1) (cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:10) (cid:1) (cid:1)(cid:2)(cid:3)(cid:3) Major assumptions (bernoulli): (cid:8)two points on a streamline (cid:8)steady flow, constant density (cid:8)incompressible (cid:8)inviscid flow. Egl = p/ g+v2/2g+z, is called the energy grade line (egl). (cid:1)the difference between the heights of egl and. Hgl is equal to the dynamic head, v2/2g. Hints for drawing hgl and egl: by definition, the egl is positioned above the hgl by an amount v2/2g. Thus if the velocity is zero, as in a lake or reservoir, the hgl and egl will coincide with the liquid surface. Hints for drawing hgl and egl: head loss for flow in a pipe or channel always means that the egl will slope downward in the direction of flow. The only exception to this rule occurs when a pump supplies energy (and pressure) to the flow.
