The decay of turbulence generated by a class of multi-scale grids

Physics – Fluid Dynamics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

41 pages, 40 figures. Accepted version of the paper prior to editorial input. Final version after editorial input available on

Scientific paper

10.1017/jfm.2011.353

A new experimental investigation of decaying turbulence generated by a low-blockage space-filling fractal square grid is presented. We find agreement with previous works by Seoud & Vassilicos (2007) and Mazellier & Vassilicos (2010) but also extend the length of the assessed decay region and consolidate the results by repeating the experiments with different probes of increased spatial resolution. It is confirmed that this moderately high Reynolds number Re{\lambda} turbulence (up to Re{\lambda} {\simeq}350 here) does not follow the classical high Reynolds number scaling of the dissipation rate {\epsilon} ~ u'^3/L and does not obey the equivalent proportionality between the Taylor-based Reynolds number Re{\lambda} and the ratio of integral scale L to Taylor micro-scale {\lambda}. Instead we observe an approximate proportionality between L and {\lambda} during decay. This non-classical behaviour is investigated by studying how the energy spectra evolve during decay and examining how well they can be described by self-preserving single-length scale forms. A detailed study of homogeneity and isotropy is also presented which reveals the presence of transverse energy transport and pressure transport in the part of the turbulence decay region where we take data (even though previous studies found mean flow and turbulence intensity profiles to be approximately homogeneous in much of the decay region). The exceptionally fast turbulence decay observed in the part of the decay region where we take data is consistent with the non-classical behaviour of the dissipation rate. Measurements with a regular square mesh grid as well as comparisons with active grid experiments by Mydlarski & Warhaft (1996) and Kang, Chester & Meveneau (2003) are also presented to highlight the similarities and differences between these turbulent flows and the turbulence generated by our fractal square grid.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The decay of turbulence generated by a class of multi-scale grids does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The decay of turbulence generated by a class of multi-scale grids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The decay of turbulence generated by a class of multi-scale grids will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-74729

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.