In a converging steady flow, the fluid is moving towards a smaller cross-sectional area. This can occur in various situations, such as flow through a nozzle or flow in a pipe with a decreasing diameter. In such a flow, three types of acceleration can be observed: convective acceleration, temporal acceleration, and local acceleration. Let's understand each of these accelerations and why only convective acceleration is present in a converging steady flow.

1. Convective Acceleration:
Convective acceleration is the change in velocity of a fluid particle as it moves from one point to another in a flow field. It is caused by the changing velocity distribution in the flow and is a result of the fluid particles being accelerated or decelerated due to the changing flow conditions. In a converging steady flow, the fluid particles experience a change in velocity as they move towards a smaller cross-sectional area. This change in velocity leads to convective acceleration.

2. Temporal Acceleration:
Temporal acceleration is the change in velocity of a fluid particle with respect to time. It is caused by a change in the velocity of a fluid particle at a fixed point in the flow field. In a steady flow, the velocity of the fluid particles at a fixed point does not change with time. Therefore, there is no temporal acceleration in a steady flow, including a converging steady flow.

3. Local Acceleration:
Local acceleration is the change in velocity of a fluid particle due to the change in flow direction at a fixed point. It occurs when the flow streamlines curve or change direction. In a converging steady flow, the flow streamlines converge towards a smaller cross-sectional area. However, since the flow is steady, the fluid particles do not change direction at a fixed point, and hence there is no local acceleration.

Therefore, in a converging steady flow, only convective acceleration is present. This is because the fluid particles experience a change in velocity as they move towards a smaller cross-sectional area, but there is no change in velocity with respect to time or change in flow direction at a fixed point.