title: Similarity of intermittency characteristics of temperature and transverse velocity.
abstract: The intermittency characteristics of the longitudinal (u) and transverse (v) velocity and temperature (theta) at similar Taylor microscale Reynolds numbers have been compared in a turbulent round jet. We examine the scaling exponents zeta_{alpha}(n) ( alpha=u , v , and theta ) of structure functions (deltaalpha);{n} , the intermittency exponents micro_{alpha} based on individual and mixed sixth-order structure functions, the scaling exponents tau;{alpha}(n) of the locally averaged energy and temperature dissipation rates approximated by ( partial differentialalpha partial differentialx);{2} , the flatness factors of the derivatives partial differentialalpha partial differentialx , and the probability density functions (PDFs) of partial differentialalpha partial differentialx , the increment deltaalpha and ( partial differentialalpha partial differentialx);{2} . It is found that v and theta are similar in terms of their intermittency characteristics. They are more intermittent than u . The scaling exponent zeta_{v}(n) is marginally larger than zeta_{theta}(n) . The intermittency exponent micro_{theta} is smaller than micro_{v} based on the estimate of mixed sixth-order structure functions, while micro_{theta} is nearly equal to micro_{v} based on the estimate of individual sixth-order structure functions. The temperature dissipation rate is more intermittent than the turbulent energy dissipation rate, as indicated by tau;{alpha}(n) . The flatness factor of partial differentialtheta partial differentialx is marginally larger than that of partial differentialv partial differentialx . The PDFs of partial differentialtheta partial differentialx , deltatheta , and ( partial differentialtheta partial differentialx);{2} show the strongest departure from the Gaussian distribution.
authors.affiliation: School of Civil Engineering, University of Sydney, NSW 2006, Australia. ggxu@optusnet.com.au
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: T
authors.initials: T
authors.lastname: Zhou
authors.forename: S
authors.initials: S
authors.lastname: Rajagopalan