An Attempt to Refute Coriolis Coiling Water in the Sink

Why do waters poured in the sink will spontaneously start a coiling flow?

ChatGPT:

When water is poured into a sink, it can sometimes spontaneously start a coiling flow, which is a fascinating phenomenon often referred to as the "fluid rope coiling" effect. This behavior can be explained by several factors:

Viscosity and Flow Rate: The viscosity of the liquid and the rate at which it is poured can influence the coiling effect. When a liquid with higher viscosity (like honey or syrup) is poured, it tends to form a coil due to its resistance to flow. However, even water, with much lower viscosity, can exhibit this behavior if poured at the right speed.

Inertia and Gravity: As the liquid falls, it gains kinetic energy due to gravity. When it hits the surface, this energy causes it to spread out. If the liquid is poured at a steady rate, the inertia of the falling stream can cause it to loop and coil upon impact.

Surface Tension: The surface tension of the liquid can also play a role. It helps the liquid maintain a cohesive stream as it falls, which can enhance the coiling effect when it hits a solid surface or another part of the liquid.

Instabilities in the Flow: Small perturbations or instabilities in the flow can lead to the coiling effect. These perturbations can be caused by imperfections in the pouring process or variations in the liquid's flow rate.

Height of Pouring: The height from which the liquid is poured can affect the coiling. A higher pouring height allows the liquid more time to develop a stable, cohesive stream before it hits the surface, which can enhance the coiling.

This phenomenon is commonly observed in everyday situations, such as when pouring syrup onto pancakes or honey into a cup of tea. It's a fascinating interplay of fluid dynamics principles that can be observed with various liquids under different conditions.

Is a coiling flow more efficient than terbulent flow ?

ChatGPT:

The efficiency of a coiling flow versus a turbulent flow depends on the context in which "efficiency" is considered. Here are some aspects to consider:

Energy Dissipation:

Coiling Flow: In a coiling flow, the motion is more orderly and less chaotic compared to turbulent flow. The energy dissipation is generally lower because the flow is smoother and involves less mixing and friction within the liquid.

Turbulent Flow: Turbulent flow is characterized by chaotic changes in pressure and flow velocity. It involves high energy dissipation due to the increased mixing and friction within the liquid.

Mixing Efficiency:

Coiling Flow: Coiling flow is less effective at mixing the liquid because it maintains a more structured and layered movement. This can be beneficial when a uniform flow is needed without much mixing.

Turbulent Flow: Turbulent flow is highly effective at mixing because it creates vortices and eddies that enhance the interaction between different parts of the liquid. This can be advantageous in processes requiring rapid and thorough mixing.

Transport Efficiency:

Coiling Flow: For transporting liquids in pipelines or conduits, a laminar (and by extension, a coiling) flow is often more efficient because it minimizes frictional losses and energy consumption.

Turbulent Flow: Turbulent flow, while generally less efficient in terms of energy consumption for transport, can be necessary in applications where mixing or heat transfer is crucial.

Heat Transfer:

Coiling Flow: The structured nature of coiling flow can limit heat transfer because there is less mixing of fluid layers.

Turbulent Flow: Turbulent flow enhances heat transfer due to the constant mixing and movement of fluid layers, which increases the contact between different temperature regions within the liquid.

Flow Stability:

Coiling Flow: Coiling flow is more stable and predictable, making it suitable for applications requiring steady and consistent flow conditions.

Turbulent Flow: Turbulent flow is inherently unstable and unpredictable, which can be a disadvantage in processes needing precise control over flow characteristics.

In summary, whether a coiling flow is more efficient than turbulent flow depends on the specific requirements of the application. Coiling flow is more efficient in terms of energy dissipation and stability, while turbulent flow is more efficient for mixing and heat transfer. The choice between the two depends on the desired outcome in a given process or application.

Is it true that in the northern hemisphere waters will spontaneously start to coil in the opposite direction than in the southern hemisphere ?

ChatGPT:

The idea that water in sinks, toilets, or bathtubs drains in opposite directions in the northern and southern hemispheres is a common myth.

This misconception is often attributed to the Coriolis effect, which is a real phenomenon that influences the direction of large-scale movements like wind patterns and ocean currents due to the Earth's rotation.

Key Points:

Coriolis Effect:

The Coriolis effect does influence large-scale phenomena such as hurricanes and ocean currents, causing them to rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.

However, the Coriolis force is extremely weak on small scales, such as in sinks, bathtubs, or toilets.

Small-scale Water Drainage:

In small-scale systems like sinks or toilets, the direction of water draining is primarily determined by the shape of the basin, the initial motion of the water, and any residual currents present.

The Coriolis effect is too weak to have a noticeable impact on the direction of water draining in these small systems.

Experimental Evidence:

Experiments have shown that in small containers, the direction of water rotation can be influenced by a variety of factors, including how the water was introduced and any minor imperfections in the basin.

In controlled environments where all other factors are minimized, the Coriolis effect can be observed, but such conditions are rarely met in everyday scenarios.

In summary, the direction of water coiling or draining in small systems like sinks or toilets is not influenced by the Coriolis effect in any significant way. Instead, it is governed by more immediate and stronger influences like the shape of the container and the initial movement of the water.

So, it's basically not true?

ChatGPT:

Yes, that's correct. The notion that water will spontaneously start to coil or drain in opposite directions in the northern and southern hemispheres due to the Coriolis effect in small-scale scenarios like sinks and toilets is not true. The Coriolis effect is too weak to have any significant influence on such small bodies of water. Instead, factors like the shape of the basin, the initial motion of the water, and any residual currents are the primary determinants of the direction in which water will drain.