TY - GEN

T1 - Modeling momentum and scalar transport in a wall-bounded turbulent flow

AU - Saxton-Fox, Theresa

AU - McKeon, Beverley

N1 - Funding Information:
The exact form of the scalar field that is correlated to the modeled velocity field has not yet been identified. However, some hypotheses can be made. From the work of Chen & Blackwelder (1978), in flows with Prandtl number near unity strong velocity gradients are known to spatially coincide with strong scalar gradients. Thus, one can expect that the strong shear layer that exists along the isocontour shown in black in figures 4 and 5 coupled with the strong velocity gradient associated with the alternating signed v regions is likely coincident with a large scalar gradient. Accurately modeling this large scalar gradient as a function of the velocity field is a subject of future work. Additionally, from the work of Antonia et al. (2009) one can hypothesize that the structure of the temperature field may be similar to some combination of the streamwise and wall-normal velocity fields identified in this work. Future work aims to create a model of the scalar field that is compatible with the velocity field model of figure 5 to shed light on the instantaneous structural relationships between the two fields. ACKNOWLEDGEMENTS The authors would like to acknowledge the support of the Air Force, which made this work possible through a National Defense Science and Engineering Graduate Fellowship and two grants overseen by Doug Smith, #FA9550-12-1-0060 and #FA9550-16-1-0361. Additionally, the authors thank Dr. Scott Dawson for his assistance with the resolvent code in the boundary layer geometry.

PY - 2017

Y1 - 2017

N2 - A mildly-heated turbulent boundary layer was studied to characterize the relationship between velocity structures and the scalar field. Particle image velocimetry (PIV) and a Malley probe (Malley et al., 1992) were used to simultaneously measure the velocity field and the streamwise gradients of the scalar field (Gordeyev et al., 2014) respectively. Two distinct velocity scales were identified to be correlated to scalar mixing by conditionally averaging the velocity field on the existence of a scalar gradient. Resolvent analysis was used to create simple models of these velocity scales (McKeon &Sharma, 2010) and to probe their interaction. Using a combination of structural conditional averaging and conditional averaging on the scalar gradient, significant interaction was observed between the two scales of interest, with behavior consistent with the general scale interaction described by amplitude modulation (Hutchins &Marusic, 2007). The study constructed a model of the velocity field that was correlated to streamwise scalar gradients in the outer boundary layer.

AB - A mildly-heated turbulent boundary layer was studied to characterize the relationship between velocity structures and the scalar field. Particle image velocimetry (PIV) and a Malley probe (Malley et al., 1992) were used to simultaneously measure the velocity field and the streamwise gradients of the scalar field (Gordeyev et al., 2014) respectively. Two distinct velocity scales were identified to be correlated to scalar mixing by conditionally averaging the velocity field on the existence of a scalar gradient. Resolvent analysis was used to create simple models of these velocity scales (McKeon &Sharma, 2010) and to probe their interaction. Using a combination of structural conditional averaging and conditional averaging on the scalar gradient, significant interaction was observed between the two scales of interest, with behavior consistent with the general scale interaction described by amplitude modulation (Hutchins &Marusic, 2007). The study constructed a model of the velocity field that was correlated to streamwise scalar gradients in the outer boundary layer.

UR - http://www.scopus.com/inward/record.url?scp=85033219274&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85033219274&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85033219274

T3 - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017

BT - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017

PB - International Symposium on Turbulence and Shear Flow Phenomena, TSFP10

T2 - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017

Y2 - 6 July 2017 through 9 July 2017

ER -