Constriction at point b reduces the cross-sectional area of the flow, causing an increase in fluid velocity. According to the continuity equation, the product of velocity and cross-sectional area must remain constant. Therefore, a decrease in cross-sectional area at point b results in an increase in velocity, which leads to an increase in flow rate before the constriction.
The degree of constriction at point b can be influenced by various factors, including the shape and size of the constriction, the viscosity of the fluid, the pressure difference before and after the constriction, and the Reynolds number of the flow. Other factors such as surface roughness and temperature can also play a role in the degree of constriction.
In most cases, constriction at point b will result in an increase in flow rate before the constriction due to the continuity equation. However, if the constriction is severe enough to cause turbulence or flow separation, it can lead to a decrease in flow rate before the constriction.
The location of point b in relation to the overall flow path can greatly influence the effect on flow rate. If point b is located near the entrance of the flow path, the constriction may have a greater impact on the flow rate. However, if point b is located further downstream, the effect on flow rate may be less significant.
In most cases, the effect of constriction at point b is reversible. If the constriction is caused by a temporary obstruction, such as a blockage, removing the obstruction will restore the flow rate to its original state. However, if the constriction is permanent, such as a narrowing in a pipe, the effect on flow rate may be irreversible unless the constriction is removed or the flow path is altered.