Home / Archive by Category "Tips & Tricks" (Page 3)

Archives

Webinar: Recent Advancements in Turbulence Modelling with Dr. Florian Menter

As part of the visit to Australia by Dr Florian Menter, world-recognised expert in turbulence modelling, LEAP Australia is pleased to announce a webinar to be held on Thursday Aug 30th at 11am AEST.  This webinar will provide an overview of recent advancements in turbulence modelling and is being held for those customers unable to attend the Advanced Turbulence training courses in Sydney, Melbourne and Perth.  More information on the training courses can be found here in a separate post. Who should attend? This webinar is suitable for all engineers, researchers & managers involved in performing CFD modelling of turbulent flows.   ABOUT THE PRESENTER Dr. Menter is a world-recognised expert in turbulence modelling. He developed the widely used Shear-Stress Transport (SST) turbulence model, which has...

10 key points covered in our CFD Meshing Tips & Tricks webinar

A quick thanks to the large number of customers in Australia and New Zealand who attended our July webinar on ANSYS CFD Meshing Tips & Tricks.  We've had many enquiries from people wanting to know more, so we thought we'd break the content down into the 10 key points below.  If you want more information on any specific point, then please contact us directly or post a comment in the field at the bottom of the page.    10 key points to a successful CFD Meshing strategy (taken from the demonstration throughout LEAP's webinar on CFD Meshing Tips & Tricks): Firstly, decide what mesh connectivity your problem requires (conformal / non-conformal) and how this will affect the setup of your geometry - single part, multi-body parts or separate...

Tips & Tricks: Turbulence Part 2 - Wall Functions and Y+ requirements

Previously we have discussed the importance of an inflation layer mesh and how to implement one easily in ANSYS Meshing.  We also touched upon the concept of mesh y+ values and how we can estimate them during the inflation meshing process.  In other posts, we also discuss the different turbulence models and eddy simulation methods available to ANSYS CFD users.  In today's post, we'll talk in more detail about y+ values apply to the most commonly used turbulence models. From our earlier discussions, we now understand that the placement of the first node in our near-wall inflation mesh is very important.  The y+ value is a non-dimensional distance (based on local cell fluid velocity) from the wall to the first mesh node, as you can see in...

Tips & Tricks: Turbulence Part 1 - Introduction to Turbulence Modelling

SAS solution in a Swirl Combustor

We will now focus on Turbulence Modelling, which is a critical area for any engineer involved with industrial CFD.  There are a number of different approaches so it is important that you have solid grounding in this area to enable you to choose the appropriate model for your simulation requirements.  It is worth noting that in August 2012, LEAP will be hosting Dr. Florian Menter to run a series of Advanced Turbulence Training courses in Melbourne, Sydney and Perth.  Dr. Menter is a world recognised expert in turbulence modelling, and more information on his visit to Australia can be found here. The ANSYS CFD Solvers solve the Navier Stokes and conservation equations, but as direct solutions are not possible to resolve for any flows of an industrial Reynolds...

Tips & Tricks: Convergence and Mesh Independence Study

RMS Residual Error Values

The previous posts have discussed the meshing requirements that we need to pay attention to for a valid result. It is important to remember that your solution is the numerical solution to the problem that you posed by defining your mesh and boundary conditions. The more accurate your mesh and boundary conditions, the more accurate your "converged" solution will be.   CONVERGENCE Convergence is something that all CFD Engineers talk about, but we must remember that the way we generally define convergence (by looking at Residual values) is only a small part of ensuring that we have a valid solution. For a Steady State simulation we need to ensure that the solution satisfies the following three conditions:   - Residual RMS Error values have reduced...

Tips & Tricks: Inflation Layer Meshing in ANSYS

Throughout our first set of Tips & Tricks posts relating to meshing controls and meshing methods, we have made mention of Inflation Layers a number of times.  Let's take this opportunity to explain exactly why inflation layers are a critical component of a good CFD mesh and how we can create them easily within ANSYS Meshing. In our first posts on Mesh Sizing we explained that as well as capturing all key features of the geometry (using local sizing and the curvature size function), we also need to have a sufficiently fine mesh to adequately capture regions where the flow will experience rapid change in key variables such as pressure, velocity or temperature.   This initially led us to a better understanding of how we should apply Global and...

Tips & Tricks: Sweep Meshing in ANSYS

Swept with Inflation

For this post, we'll discuss a topic which allows you to complement your understanding of global and local mesh controls that we have covered previously.  Sweep meshing is a meshing method available in ANSYS Meshing that is important for all CFD users to understand and can be readily used to maintain high solver accuracy at the same time as reducing mesh cell counts (leading to a serious speedup in solve times).   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...

Tips & Tricks: Size Controls in ANSYS

In our previous post we discussed the importance of geometry preparation, utilising the ANSYS Global Mesh Control settings and the best use of the ANSYS Meshing Advanced Size Functions.  We will now focus on the ability to target specific areas of the mesh for additional refinement and mesh control, which is recommended for intermediate to advanced users.   [box] By using these explicit sizing controls, the resolution of the geometry can be accurately captured and we can ensure that we accurately resolve any high gradient areas in the flow, such as a wake or separation/recirculation zones.[/box]   As you would expect, in addition to the automated settings, ANSYS Meshing provides users with as much additional control as they desire: with the option to specify combinations of...

Tips & Tricks: Global Meshing Controls in ANSYS

Welcome to the first in LEAP's series of CFD Tips & Tricks blogs.  The topics for this first series of blog entries will focus on the selection of efficient and appropriate meshing methods, mesh sizing and mesh controls in ANSYS Workbench Meshing.  Meshing is one of the most important influences on CFD simulation accuracy, although it does not necessarily need to be the most time intensive.   In our experience, our ANSYS CFD customers become more confident and efficient with meshing as they gain a better understanding of the importance of certain mesh settings and the likely effect of these settings on final solution accuracy. Where to start? After defining your project scope and the key variables of interest (either geometric and/or boundary/operational conditions), the first step...

1 2 3