2,000
Views
323
CrossRef citations to date
0
Altmetric
Original Articles

A public turbulence database cluster and applications to study Lagrangian evolution of velocity increments in turbulence

, , , , , , , & show all
Article: N31 | Received 04 Apr 2008, Accepted 28 Jul 2008, Published online: 06 Oct 2008
 

Abstract

A public database system archiving a direct numerical simulation (DNS) data set of isotropic, forced turbulence is described in this paper. The data set consists of the DNS output on 10243 spatial points and 1024 time samples spanning about one large-scale turnover time. This complete 10244 spacetime history of turbulence is accessible to users remotely through an interface that is based on the Web-services model. Users may write and execute analysis programs on their host computers, while the programs make subroutine-like calls that request desired parts of the data over the network. The users are thus able to perform numerical experiments by accessing the 27 terabytes (TB) of DNS data using regular platforms such as laptops. The architecture of the database is explained, as are some of the locally defined functions, such as differentiation and interpolation. Test calculations are performed to illustrate the usage of the system and to verify the accuracy of the methods. The database is then used to analyze a dynamical model for small-scale intermittency in turbulence. Specifically, the dynamical effects of pressure and viscous terms on the Lagrangian evolution of velocity increments are evaluated using conditional averages calculated from the DNS data in the database. It is shown that these effects differ considerably among themselves and thus require different modeling strategies in Lagrangian models of velocity increments and intermittency.

Acknowledgment

The authors thank Tamas Budavari, Ani Thakar, Jan Vandenberg and Alainna Wonders for their valuable help at various stages of development and maintenance of the database cluster. They also wish to acknowledge the National Science Foundation for funding through the ITR program, grant AST-0428325. The DNS was performed on a cluster supported by NSF through MRI grant CTS-0320907. Additional hardware support was provided by the Moore Foundation. Discussions with Professor Ethan Vishniac are also gratefully acknowledged.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.