Ever questioned methods to visualize the invisible forces shaping your designs? SOLIDWORKS Stream Simulation has choices to visualise the boundary layers and y-plus parameters.
Within the realm of computational fluid dynamics (CFD), understanding the conduct of the boundary layer and y-plus values is essential for optimizing your designs. These parameters present insights into the circulation traits close to surfaces, which may considerably affect efficiency and effectivity.
What’s Y-plus?
Y-plus is a dimensionless parameter utilized in computational fluid dynamics to explain the gap from the wall to the primary cell middle within the mesh. It’s important for precisely predicting the conduct of the boundary layer, which is the skinny area of fluid close to a strong floor the place viscous forces are vital.
In contrast to in different CFD applications, with SOLIDWORKS Stream Simulation we shouldn’t have to fret concerning the y-plus worth or the cell measurement close to the wall as they’re dealt with internally by the software program. This inner dealing with is among the many explanation why SOLIDWORKS Stream Simulation is less complicated to arrange than different CFD software program applications.
Default Boundary Layer in SOLIDWORKS Stream Simulation
The default boundary layer kind is decided by SOLIDWORKS Stream Simulation primarily based on the Reynolds quantity and outlined by the equal hydraulic diameter. The layer thickness is decided by the efficient wall size and is ruled by the Reynolds Quantity.
The boundary layer parameters on the mannequin partitions close to inlets are all the time specified by default in SOLIDWORKS Stream Simulation. Within the exterior circulation evaluation instance proven within the picture beneath, we have now a neighborhood mesh outlined across the frisbee. The finer mesh across the object will enable for greater constancy and higher visualization of the boundary layer. The y-plus parameter is a sign of the proximity of the primary cell to the floor or wall. If the boundary layer just isn’t resolved adequately, the values of y-plus gained’t be correct. It’s because it will depend on the speed gradients on the wall, which itself will depend on the mesh decision. Per the SOLIDWORKS Stream Simulation technical reference: the software program offers a “Two-Scale Wall Perform” mannequin that consists of two approaches to couple the boundary layer calculation with the primary circulation properties.
SOLIDWORKS Stream Simulation native mesh management
One methodology is the “skinny boundary layer strategy” which describes boundary layers on a rough mesh with six or fewer cells throughout the boundary layer. On this strategy, the Prandtl boundary layer equations are already built-in alongside the traditional for the wall. This begins from zero and extends to the dynamic boundary layer thickness fixing alongside a fluid streamline close to the wall. The identical strategy is used for the thermal and focus boundary layers the place every boundary layer is taken into account with its thickness.
To explain boundary layers on a advantageous mesh with six or extra cells throughout the boundary layer the “thick boundary layer” strategy is used. On this strategy, the calculation of parameters of laminar boundary layers is finished through the Navier-Stokes equation, and for the turbulent boundary layer, a modification of the well-known “wall operate” strategy is employed.
We don’t should manually select one of many approaches since an applicable boundary layer strategy is mechanically chosen by SOLIDWORKS Stream Simulation. As soon as the evaluation is full, you may show the boundary layer by enabling the choice in Cutplot.
Displaying boundary layer in Lower Plot
Viewing Y-plus
To view the y-plus, you may outline a customized visualization parameter utilizing shear stress, density, wall distance, and dynamic viscosity. Y-plus is a non-dimensional parameter and will be plotted utilizing a floor plot. A low worth of y-plus between one and thirty is appropriate for many sensible purposes balancing end result accuracy and computational value.
Y-plus Floor Plot
Mesh High quality for Correct Stream Simulations
To find out if the mesh is sweet sufficient for an correct resolution you may embrace an extra aim similar to drive or torque to watch the change in its worth when the mesh is refined in subsequent iterations. If the worth doesn’t change a lot with additional mesh refinement, then the mesh and boundary layer (together with y-plus) are precisely resolved. Understanding y-plus values is crucial for correct and environment friendly circulation simulations, notably in purposes involving complicated geometries and turbulent flows.
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