正浮力による乱流後流での大規模運動の二重構造化とその構造不安定(熱工学, 内燃機関, 動力など)
2001 年 67 巻 662 号 p. 2541-2549
詳細
2001 年 67 巻 662 号 p. 2541-2549
A positively buoyant wake from a circular cylinder at the Reynolds number 800∿940 is measured, discussed and found as follows : By heating an isothermal wake, turbulent energy and turbulent vorticity in the isothermal turbulent wake are conserved in the buoyant wake, and this buoyant wake certainly becomes a double structure combined non linearly with two kinds of large-scaled coherent motions, i.e. one is the vortex street motion and the other the plume swaying motion with extremely different frequencies each other. That is, the buoyant wake is a turbulent flow with a triple structure of free turbulence, vortex motion and swaying motion. Structural instability with abrupt change occurs certainly due to unbalance between two kinds of large scaled motions.
