Pipe narrowing
Basic contraction
"Simulate water flowing through a pipe that narrows from 10cm to 5cm diameter over a 20cm transition length. Inlet velocity is 1 m/s."
What SimPilot does: Creates a 2D axisymmetric or 3D pipe geometry, generates a structured mesh with refinement in the contraction zone, and runs simpleFoam with k-epsilon turbulence. Reports pressure drop and maximum velocity.
Sudden expansion
"Model flow through a pipe that suddenly expands from 5cm to 15cm diameter. Water at 2 m/s inlet. I want to see the recirculation zone."
What SimPilot does: Sets up a simulation capturing the recirculation zone downstream of the expansion. Uses pimpleFoam for the transient features and generates streamline visualizations.
Y-junction
Splitting flow
"Simulate water flow splitting at a Y-junction. Main pipe is 10cm diameter, two branches are 7cm each at 45-degree angles. Inlet velocity 1.5 m/s."
What SimPilot does: Creates the Y-junction geometry, generates an unstructured mesh with snappyHexMesh, and runs an incompressible flow simulation. Reports the flow split ratio between branches.
Mixing junction
"Two pipes (8cm diameter each) merge into a single 12cm pipe at a Y-junction. One carries water at 20°C, the other at 80°C. Both at 0.5 m/s. Show me the temperature mixing."
What SimPilot does: Uses buoyantSimpleFoam or buoyantPimpleFoam with energy equation enabled. Visualizes the temperature field to show thermal mixing downstream of the junction.
Elbow flow
90-degree elbow
"Simulate turbulent water flow through a 90-degree pipe elbow. Pipe diameter 8cm, mean velocity 3 m/s. Show the secondary flow pattern."
What SimPilot does: Creates the curved pipe geometry, generates a refined mesh capturing the secondary Dean vortices, and runs with k-omega SST turbulence model. Visualizes cross-sectional velocity profiles at various positions around the bend.
S-bend
"Model flow through an S-shaped pipe bend (two 90-degree bends in opposite directions). Pipe diameter 10cm, velocity 2 m/s. Calculate the total pressure loss."
What SimPilot does: Sets up the double-bend geometry and computes total pressure drop. Compares with straight pipe losses to quantify the additional loss from the bends.
For pipe flows, SimPilot automatically calculates the Reynolds number and selects appropriate turbulence modeling. Laminar flows (Re < 2300) use icoFoam, while turbulent flows use simpleFoam or pimpleFoam with RANS turbulence models.