<div dir="ltr">
<div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial">Hello All,</div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial">I am currently investigating the turbulence in a pipe with periodic boundary conditions. I am working on building my mesh and was planning on using Re^(3/4) as the number of elements per characteristic length, but I have found differing methods in literature detailing the number of elements used for DNS. One paper in particular (G.K. El Khoury et al, Direct Numerical Simulation of Turbulent Pipe Flow at Moderately High Reynolds Numbers, Flow Turbulence Combust, 2013) uses Nek5000 to simulate turbulent flow in a pipe at different Reynolds numbers. The number of elements calculated in this paper seem to be in between the LES and DNS suggested number of elements (element size between the Taylor microscale and the Kolmogorov scale). Turbulent Flows by Pope however suggests a number of elements that is slightly larger than Re^(3/4), and is dependent on the Taylor microscale Reynolds number. </div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial">Any suggestions on the correct way to determine the number of spectral elements in a characteristic length would be appreciated.</div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial">Regards,</div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:12.8px;text-decoration-style:initial;text-decoration-color:initial">Tommy</div>
<br></div>