TY - JOUR
T1 - Controlling spatio-temporal evolution of natural and excited square jets via inlet conditions
AU - Tyliszczak, Artur
AU - Geurts, Bernardus J.
PY - 2019/12
Y1 - 2019/12
N2 - The paper presents numerical investigations of square jets in a wide range of Reynolds numbers with varying inlet turbulence characteristics. The research focuses on flow characteristics depending on inflow turbulent length/time scales and excitation frequencies in case of excited jets. It is found that the parameters of inlet turbulence affect the solutions qualitatively when the Reynolds number is sufficiently low. In these cases the impact of varying the turbulent time scale is considerably larger than changing the turbulent length scale. It was also observed that at sufficiently high Reynolds numbers the jets become quite independent of the inlet turbulence characteristics. This confirms findings of Xu et al. (Phys. Fluids, 2013) concerning weak/strong dependence of the jet evolution on inflow conditions. In case of excited jets the excitation frequencies play an important role and influence the jet behaviour most strongly at lower values of the Reynolds number. For some forcing frequencies a bifurcation occurs at sufficiently large forcing amplitudes. This phenomenon turned out to be independent of the assumed length and time scales of the turbulent fluctuations, both in terms of robustness as well as amplitude.
AB - The paper presents numerical investigations of square jets in a wide range of Reynolds numbers with varying inlet turbulence characteristics. The research focuses on flow characteristics depending on inflow turbulent length/time scales and excitation frequencies in case of excited jets. It is found that the parameters of inlet turbulence affect the solutions qualitatively when the Reynolds number is sufficiently low. In these cases the impact of varying the turbulent time scale is considerably larger than changing the turbulent length scale. It was also observed that at sufficiently high Reynolds numbers the jets become quite independent of the inlet turbulence characteristics. This confirms findings of Xu et al. (Phys. Fluids, 2013) concerning weak/strong dependence of the jet evolution on inflow conditions. In case of excited jets the excitation frequencies play an important role and influence the jet behaviour most strongly at lower values of the Reynolds number. For some forcing frequencies a bifurcation occurs at sufficiently large forcing amplitudes. This phenomenon turned out to be independent of the assumed length and time scales of the turbulent fluctuations, both in terms of robustness as well as amplitude.
KW - Bifurcation phenomenon
KW - Flow control
KW - Inlet conditions
KW - Jet near-field
KW - 22/4 OA procedure
UR - http://www.scopus.com/inward/record.url?scp=85073560482&partnerID=8YFLogxK
U2 - 10.1016/j.ijheatfluidflow.2019.108488
DO - 10.1016/j.ijheatfluidflow.2019.108488
M3 - Article
AN - SCOPUS:85073560482
VL - 80
JO - International journal of heat and fluid flow
JF - International journal of heat and fluid flow
SN - 0142-727X
M1 - 108488
ER -