TY - JOUR
T1 - Structural characteristics of a heated jet in cross-flow emanating from a raised, circular stack
AU - Johnson, Blake E.
AU - Elliott, Gregory S.
AU - Christensen, Kenneth T.
N1 - This work was supported through an STTR Phase I and Phase II project awarded to IllinoisRocstar LLC, STTR N07-T001; Phase I Contract #N00014-07-M-0355 funded by the Office of Naval Research, Phase II Contract #N68335-08-C-0287 funded by the Naval Air Systems Command. Funding from the U. of Illinois is also gratefully acknowledged.
PY - 2013/6
Y1 - 2013/6
N2 - The structural characteristics of a jet heated to 425 K and emitted from a raised, circular stack into a 300 K cross-flow were studied via cross-plane stereo particle-image velocimetry measurements at multiple streamwise locations downstream of the stack exit. Similar measurements of an unheated jet at equivalent Reynolds number and similar blowing ratio provided a baseline of comparison for the heated case. Instantaneous velocity fields for the heated and unheated jets were marked by intense, small-scale vortices and only a weak indication of a counter-rotating vortex pair (CVP). Upon filtering by proper orthogonal decomposition (POD) to recover only the large-scale flow features, the imprint of the CVP was clearly discerned in the instantaneous fields. The CVP of the heated jet was stronger as well as larger and advected further into the cross-flow compared to that of the unheated jet. While this large-scale reconstruction by POD embodied 35 % of the turbulent kinetic energy, it was found that these large-scale motions captured a vast majority of the Reynolds shear stress, indicating a predominance of the CVP in this regard.
AB - The structural characteristics of a jet heated to 425 K and emitted from a raised, circular stack into a 300 K cross-flow were studied via cross-plane stereo particle-image velocimetry measurements at multiple streamwise locations downstream of the stack exit. Similar measurements of an unheated jet at equivalent Reynolds number and similar blowing ratio provided a baseline of comparison for the heated case. Instantaneous velocity fields for the heated and unheated jets were marked by intense, small-scale vortices and only a weak indication of a counter-rotating vortex pair (CVP). Upon filtering by proper orthogonal decomposition (POD) to recover only the large-scale flow features, the imprint of the CVP was clearly discerned in the instantaneous fields. The CVP of the heated jet was stronger as well as larger and advected further into the cross-flow compared to that of the unheated jet. While this large-scale reconstruction by POD embodied 35 % of the turbulent kinetic energy, it was found that these large-scale motions captured a vast majority of the Reynolds shear stress, indicating a predominance of the CVP in this regard.
UR - https://www.scopus.com/pages/publications/84878731508
UR - https://www.scopus.com/pages/publications/84878731508#tab=citedBy
U2 - 10.1007/s00348-013-1543-1
DO - 10.1007/s00348-013-1543-1
M3 - Article
AN - SCOPUS:84878731508
SN - 0723-4864
VL - 54
JO - Experiments in Fluids
JF - Experiments in Fluids
IS - 6
M1 - 1543
ER -