ANS:C -

Uniform fluid flow occurs when the derivative of the flow variables with respect to spatial coordinates (typically with respect to position or distance) is zero. In mathematical terms, for a flow variable ϕ\phiϕ (such as velocity, pressure, or temperature), uniform flow implies: ∂ϕ∂x=0\frac{\partial \phi}{\partial x} = 0∂x∂ϕ​=0 where xxx represents the spatial coordinate along the direction of flow (e.g., along a pipe or channel). This condition means that the flow variable ϕ\phiϕ does not change with position along the flow direction. In other words, the flow is steady and homogeneous along the direction of interest, indicating no spatial variations in the flow properties. Uniform fluid flow is an idealized condition often assumed in fluid dynamics analyses to simplify calculations and understand basic flow behaviors. However, in real-world scenarios, flows are often non-uniform due to various factors such as viscosity effects, turbulence, flow instabilities, and boundary conditions.