In sub-critical flow transition, the emphasis is essentially to provide smooth and gradual changes in the boundary to prevent flow separation and consequent energy losses. Even if slight change the curvature in transition, the boundary zone of the retarded liquid expands rapidly. Its impact on velocity distributions which become highly uneven with corresponding large values of energy coefficient (α) & momentum coefficient () and fluid flow may fail completely to flow the channel walls. Several experimental studies carried out before to find out the losses in the abrupt expansion (Hinds 1928; Formica, 1955; Smith and Yu, 1966; Mazumdar, 1967; Nashta and Garde, 1988).
The channel transition ratio (B/b) has a significant influence upon the …show more content…
V1= Velocity at inlet in channel transition.
V2= Velocity at inlet in channel transition. (2.3) where, is the energy loss along the channel length, is the loss coefficient whose value varies between 0.2 and 0.3, and
Daugherty et al. (1954) determined energy losses in a closed conduit with a sudden transition as (2.4) where = energy loss in the transition. = the loss …show more content…
Author plotted the curves in between the Froude number and loss coefficient. The plotted curve showed that the geometry and Froude number both influence the loss of energy in the expansion channel. The author compared the head losses between the different types of transition and concluded that the smooth S-shape curve transition had low head loss coefficient but S-shape curve with vanes obtained the highest head loss coefficient which was unexpected by the author. With the exception of the S-shape curve all other transition displayed some separation. The result indicated that the optimum flow pattern obtained in S-shape walls rather than straight segment channel transition.
Skogerboe et al. (1971) studied the energy loss analysis in open channel transition. Authors compared the result in head loss in open channel transition reported by the previous investigator. Skogerboe et al. (1971) showed that coefficient used in head loss calculation are not constant, but it is a function of the inlet Froude no and transition ratio. Morris & Wiggert (1972) and Brater & King (1976) determined the constant empirical local loss coefficients for transition
The channel transition ratio (B/b) has a significant influence upon the …show more content…
V1= Velocity at inlet in channel transition.
V2= Velocity at inlet in channel transition. (2.3) where, is the energy loss along the channel length, is the loss coefficient whose value varies between 0.2 and 0.3, and
Daugherty et al. (1954) determined energy losses in a closed conduit with a sudden transition as (2.4) where = energy loss in the transition. = the loss …show more content…
Author plotted the curves in between the Froude number and loss coefficient. The plotted curve showed that the geometry and Froude number both influence the loss of energy in the expansion channel. The author compared the head losses between the different types of transition and concluded that the smooth S-shape curve transition had low head loss coefficient but S-shape curve with vanes obtained the highest head loss coefficient which was unexpected by the author. With the exception of the S-shape curve all other transition displayed some separation. The result indicated that the optimum flow pattern obtained in S-shape walls rather than straight segment channel transition.
Skogerboe et al. (1971) studied the energy loss analysis in open channel transition. Authors compared the result in head loss in open channel transition reported by the previous investigator. Skogerboe et al. (1971) showed that coefficient used in head loss calculation are not constant, but it is a function of the inlet Froude no and transition ratio. Morris & Wiggert (1972) and Brater & King (1976) determined the constant empirical local loss coefficients for transition