  We find capillary wave turbulence (WT) to span multiple dynamical regimes and
geometries -- from weakly to strongly nonlinear WT (SWT) and from shallow to
deep domains -- all within a 40uL volume millifluidic system. This study is
made viable with recent advances in ultra-high-speed digital holographic
microscopy, providing 10-us time and 10-nm spatial resolutions for images
across the entire field of view, and encompassing a complete wave system at
speeds sufficient to capture the salient wave phenomena. We provide a set of
tractable parameters that identify the four fundamental WT regimes present in
this simple system. A proposed nonlinearity measure permits comparative
analysis while varying input conditions. This work augments current
understanding of WT regimes and behaviors, and directly applies to many fields
beyond fluid mechanics. For example, SWT appears upon the fluid interface at
powers less than required for atomization, indicating that further study of SWT
is needed to properly understand ultrasound-driven fuel spray atomization and
drug and agricultural nebulization.

Fluid Dynamics