Parabolic inlet velocity profile that varies with time

Problem Statement:

It is a laminar pipe flow problem, the inlet velocity profile is parabolic and it varies Sinusoidally with respect to the flow time. Finding out the time vs Velocity graph at the inlet. Simulating the problem by using the named expression in fluent solver.

The surface parameters s1 and s2 in 3D are available on boundaries (faces). They can be difficult to use because the relationship between x, y, and z (the spatial coordinates) and s1 and s2 is nonlinear. Often it is more convenient to use expressions with x, y, and z for specifying distributed boundary conditions. To see the values of s1 and s2, plot them using a surface plot.
Reading between the lines of your post, I understand that in 3D your channel is a cylinder and your inlet is a disc. If that disc is in the x, y plane and centred at x0,y0,0, you could simply use an expression along the lines of U0*(1-((x/x0)^2+(y/y0)^2)). Alternatively, you could define an additional, cylindrical coordinate system with its origin at x0,y0,0, and use an expression along the lines of U0*(1-(sys2.r/Radius)^2)

CFD:

Computational Fluid Dynamics (CFD) is the process of mathematically modelling a physical phenomenon involving fluid flow and solving it numerically using the computational process.

In a CFD software analysis, the examination of fluid flow by its physical properties such as velocity, pressure, temperature, density, and viscosity. To generate an accurate solution for a physical phenomenon associated with fluid flow, those properties must be considered simultaneously.

A mathematical model of the physical case and a numerical method are used in a CFD software tool to analyze the fluid flow. For instance, the Navier-Stokes (N-S) equations are specified as the mathematical model of the physical case. This describes changes in all those physical properties for both fluid flow and heat transfer. A mathematical model varies by the content of the problem such as heat transfer, mass transfer, phase change, chemical reaction, etc. Moreover, the reliability of a CFD analysis highly depends on the whole structure of the process.

Theory:

Geometry:

Meshing:

Sweep Method:

The Sweep Method begins by meshing a particular 'source' surface using either the automatic global settings or any local sizing controls/inflation layers that have been applied by the user. It will then "sweep" the source mesh (which can represent any arbitrary cross-section) through the body, spacing it by a certain incremental dimension or by splitting the swept side faces into a desired number of divisions.

It is useful when you first open ANSYS Meshing to Right-click on "Mesh" in the left-hand model tree and choose the option to “Show" -> "Sweepable Bodies”. Upon choosing this option, any bodies within your assembly that can be swept automatically will be shown in green on your screen.