Fluid Mechanics local acceleration and convective acceleration

[yrael]

Homework Statement

The velocity of the water in the pipe is given by v1=.5t m/s and v2=1tm/s, where t is in seconds. Determine the local acceleration at points 1 and 2. Is the average convective acceleration between these two points negative, zero, or positive?

Homework Equations

A figure of pipe (funnel like) that is larger at the input end with v1 and smaller end without put speed of v2.

The Attempt at a Solution

I don't really know how to start answering this question, I don't have the text with me (still in delivery) and don't have any notes that's on this topic.

My try: d (v1)/dt=0.5t so a=d(v1)/dt=.5 m/s^2
d(v2)/dt=1t so a2=d(v2)/dt=1 m/s^2

 

[Shooting Star]

The local accn changes because the flow is not steady and time dependent, and the values are as you have derived.

The convective accn is positive because a particle of fluid has to speed up due to the area at point 2 being smaller than area at point 1.

For a steady flow, there would be convective accn only.