Transport Phenomena Academy: Fluid Mechanics, Heat & Mass Transfer
This working group covers Fluid Mechanics, Heat & Mass Transfer, required for understanding... View more
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Vortex Vorticities and Eddies in Fluid Dynamics
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Vortex Vorticities and Eddies in Fluid Dynamics
Vortex, Vorticities and Eddies in Fluid Dynamics, differences, similarities, origins and relationships? Do we have Vortex, Vorticities and Eddies also in Laminar Flows?
Thanks to Zainab Amjad for opening this interesting question during our Turbulence Course (https://lnkd.in/ewgQD3uz). These important concepts sometimes becomes confusing.
Vorticity:
Vorticity is a defined :mathematical vector quantity: that describes the local rotation of fluid elements within a flow (curl of the velocity field). In simple terms, vorticity measures the tendency of fluid parcels to rotate around their local axes. A non-zero vorticity indicates the presence of rotational motion in the flow, which can happen in laminar or turbulent conditions. However appearing vorticities in laminar flow can be an initiation towards turbulence, however not necessarily.
Vortex:
A Vortex is “A physical region within a fluid flow” where the fluid rotates around an imaginary axis line. It is characterized by swirling motion, typically forming structures such as spirals or whirlpools. Vortex can arise due to various mechanisms, such as the presence of solid boundaries, shear in the flow, or the interaction of different flow streams. Vortexes play crucial roles in fluid dynamics, influencing phenomena such as lift and drag on objects, mixing, and flow stability.
Regarding the presence of the vorticity and vortex in laminar/turbulent flows:
-In laminar flow, fluid motion is smooth and orderly, with well-defined streamlines. While vortexes may still form in laminar flow, they are typically smaller and less pronounced compared to turbulent flow. Similarly, vorticity exists in laminar flow, but it is often confined to specific regions, such as near solid boundaries or in regions of shear, where rotational motion occurs. The vorticity in laminar flow is generally more uniform and organized compared to turbulent flow.
In turbulent flow, fluid motion is characterized by chaotic and irregular fluctuations, with high levels of mixing and eddy formation. Vortexes in turbulent flow are larger, more energetic, and more prevalent compared to laminar flow. Turbulent flows exhibit significant vorticity throughout the flow field, with Vortexes continuously forming, interacting, and dissipating. The vorticity in turbulent flow is highly dynamic spatially and temporally.
Eddies:
Eddies are commonly associated with turbulent flows, however they can also occur in laminar flows in smaller scales. Eddies and vorticity are closely related, vorticity often being a precursor to the formation of eddies from very small to very large scales.
We may say, vortex is integration of many temporary vorticities and eddies that appear and dissipate, while vortexes are continuous alive mean flow structure .
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