******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear Nektar++ developers, I am working on numerical simulation of blood flow in arteries. The flow regime of my case study is laminar. In addition to obtaining velocity and pressure field, the evaluation of shear rate and WSS for this case is also important for me. Therefore, in addition to using tetrahedral elements as core mesh, I am going to employ prism layers for resolving the boundary layer next to the wall. I have seen, in the literature, that there are two approaches for producing the boundary layer mesh that most groups use them. Firstly, some groups consider a constant total thickness for boundary layer mesh. This means that during the mesh study process, they do not change the overall thickness but they try to increase the number of layers. Secondly, other groups consider a constant number of layers for the boundary layer mesh (e.g. three layers for the coarse mesh) during the mesh study and when they refine the mesh in each step, the element size of each layer decreases. As a result, the total thickness of boundary layer mesh decreases too. Meanwhile, I have encountered some questions related to these approaches for producing boundary layer mesh. I have seen in articles related to the blood flow simulation which is done using Nektar++, p-refinement method has been used for mesh study process which I think this mimics the first approach. My question is that how I can calculate the total thickness of the boundary layer mesh (both steady and pulsatile flow conditions) through the mesh study. Related to the second approach, I have seen different research teams have various opinions for constructing the boundary layer mesh even for the cases with similar geometry and flow conditions. For example, different groups produce boundary layer mesh with a range of 3 to 20 layers. In addition, some consider a constant thickness for “each” layer (with no growth factor). However, others try to use a growth factor to vary the thickness of each layer. Even, different groups use a variety of core element size to boundary layer size ratio to construct the mesh. I know that this depends on the case study but they did not mention any reason for their choices. I would like to know whether or not there is a rule of thumb for this process or if there is a good guess for producing the boundary layer mesh with respect to this approach. I would be wondering if you could guide me on these issues. Best regards, Ezat Shokrani,