Drop Decay into Individual Fibers at the Boundary of the Contact Area with a Target Fluid

IOP Conf. Ser.: Earth Environ. Sci.

2022

To calculate the dynamics and structure of flows, a system of fundamental equations of fluid mechanics with equations of state for the Gibbs potential and density of an inhomogeneous medium is applied. The complete solution of the system describes ligaments, waves, vortices, jets, wakes, and other types of flows. Calculations of flow patterns around obstacles are consistent with the experiment. Observations of the processes of merging a freely falling drop with a target fluid revealed that the finest components are formed during the direct generation of ligaments by atomic-molecular processes. The involvement of a scaled and parametrically invariant system of fundamental equations permits the study of unsteady energetic flows and more accurately describes their dynamics and structure in the whole range of scales from microscopic to global.

Section: Hydrodynamics Of a Drop Impactmentioning

confidence: 98%

Section: Hydrodynamics Of a Drop Impactmentioning

confidence: 99%

Atomic-molecular effects in geophysical hydrodynamics

IOP Conf. Ser.: Earth Environ. Sci.

2022

“…Similarly to the basic equations of motion, the boundary conditions (46) can also be obtained from the boundary conditions (13) using a limit transition N → 0 . Substitution of the solution in the form of a propagating wave…”

Section: Reduction To Approximation Of Actually Homogeneous Fluidmentioning

confidence: 99%

“…In the field of propagating gravitational-capillary waves (5 < ω < 50 Hz), the substance of the colored drop is distributed unevenly over the surface of the primary cavity [45], the same as in the case of a drop merging with a target liquid at rest [46]. In the evolutionary process a slowly drifting colored primary contact area, a near-surface jet with a vortex head and a sinking ring vortex remain in the distribution pattern of the substance.…”

Section: Introductionmentioning

confidence: 99%

Periodic Waves and Ligaments on the Surface of a Viscous Exponentially Stratified Fluid in a Uniform Gravity Field

Очиров

2022

Axioms

The theory of singular perturbations in a unified formulation is used, for the first time, to study the propagation of two-dimensional periodic perturbations, including capillary and gravitational surface waves and accompanying ligaments in the 10−4<ω<103 s−1 frequency range, in a viscous continuously stratified fluid. Dispersion relations for flow constituents are given, as well as expressions for phase and group velocities for surface waves and ligaments in physically observable variables. When the wave-length reaches values of the order of the stratification scale, the liquid behaves as homogeneous. As the wave frequency approaches the buoyancy frequency, the energy transfer rate decreases: the group velocity of surface waves tends to zero, while the phase velocity tends to infinity. In limiting cases, the expressions obtained are transformed into known wave dispersion expressions for an ideal stratified or actually homogeneous fluid.

“…The substance of a rapidly falling drop is distributed over the surface of the target fluid in the form of thin fibers that constitute regular linear and reticular structures on the surface of the cavity and crown [78,79]. The fibrous distribution pattern of the drop substance was observed for a long time in a deep [80] fluid at rest, in a shallow target fluid [81], as well as in the field of running gravitational-capillary waves [82].…”

Section: Introductionmentioning

confidence: 99%

Intrusive and Impact Modes of a Falling Drop Coalescence with a Target Fluid at Rest

Ilinykh

2023

Axioms

The evolution of the falling drop substance transfer in a target fluid at rest was traced by high-speed video techniques. Two flow modes were studied: slow intrusive flow, when the KE of the drop was comparable or less than the available potential energy (APSE), and a fast impact flow, at a relatively high drop contact velocity. For the substance transfer visualization, a drop of alizarin ink solution at various concentrations was used. The use of transparent partially colored fluid allows tracing the drop matter motion in the bulk and on the fluid free surface. The traditional side and frontal view of flow patterns were registered and analyzed. In both flow modes, the substance of the drop partially remained on the free surface and partially went into the target fluid bulk, where it was distributed non-uniformly. In the intrusive mode, the drop substance partially remained on the surface, while the main mass of the drop flowed into the thickness of the target fluid, forming the lenticular colored domain. The intrusion was gradually transformed into an annular vortex. In the impact mode, the drop broke up into individual fibers during the coalescence, creating linear and reticular structures on the surface of the cavity and the crown. The flow patterns composed of individual fibers were rapidly rebuilt as the flow evolved and the splash emerged and decayed. The sizes of cavities and colored fluid domains were compared in different flow regimes as well. The total energy transfer and transformation impact on the flow structure formation and dynamics was revealed.