Shaltiel Omri, Salhov Alon, Gat Omri, Sharon Eran
Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel.
Phys Rev Lett. 2024 May 31;132(22):224001. doi: 10.1103/PhysRevLett.132.224001.
A short, abrupt increase in energy injection rate into steady strongly driven rotating turbulent flow is used as a probe for energy transfer in the system. The injected excessive energy is localized in time and space and its spectra differ from those of the steady turbulent flow. This allows measuring energy transfer rates, in three different domains: In real space, the injected energy propagates within the turbulent field, as a wave packet of inertial waves. In the frequency domain, energy is transferred nonlocally to the low, quasigeostrophic modes. In wave number space, energy locally cascades toward small wave numbers, in a rate that is consistent with two-dimensional (2D) turbulence models. Surprisingly however, the inverse cascade of energy is mediated by inertial waves that propagate within the flow with small, but nonvanishing frequency. Our observations differ from measurements and theoretical predictions of weakly driven turbulence. Yet, they show that in strongly driven rotating turbulence, inertial waves play an important role in energy transfer, even in the vicinity of the 2D manifold.
向稳定的强驱动旋转湍流中短时间突然增加能量注入率，以此作为系统中能量传递的一个探针。注入的过量能量在时间和空间上是局部化的，其频谱与稳定湍流的频谱不同。这使得能够在三个不同的领域测量能量传递率：在实空间中，注入的能量作为惯性波的波包在湍流场中传播。在频域中，能量非局部地传递到低阶准地转模式。在波数空间中，能量以与二维（2D）湍流模型一致的速率局部地向小波数级联。然而，令人惊讶的是，能量的反向级联是由在流中以小但不为零的频率传播的惯性波介导的。我们的观测结果与弱驱动湍流的测量结果和理论预测不同。然而，它们表明，在强驱动旋转湍流中，即使在二维流形附近，惯性波在能量传递中也起着重要作用。
