8.5.1. Tidal Energy Harvesting

Let me give a simple example of the tidal energy, which nowadays very famous for the cases of getting the renewable energies. The tidal energy harvesters are nowadays very interesting components are there.

Tidal energy harvesting involves capturing energy generated by the rise and fall of tides. This method of energy production is gaining popularity as a renewable energy source. Tidal energy harnesses the kinetic and potential energy from the ocean's tides, which are caused by the gravitational interactions between the Earth, moon, and sun. As tides rise and fall, they can be used to turn turbines and generate electricity.

Think of tidal energy like a water wheel in a river. Just as the flowing river turns the wheel to produce energy, the movement of the tides can turn turbines placed underwater, generating electricity that can power homes and businesses.

Like for examples, you will have a bed. You construct a turbine and the flow comes like this. This is the tidal which comes from these, this is the upstream, this is the downstream and you try to look at this is the air, this is the waters, You try to solve these problems using computational fluid dynamics or you try to solve analytically to know it how much of energy harvesters will be there if I just put a turbine below a sea level where the tidal waves will rotate these turbines and we can harvest the energy.

In a tidal energy harvesting system, turbines are placed in water bodies where tidal movements occur. As the water level rises and falls with the tides, it creates a flow of water that can turn these turbines. When the turbines spin, they generate electricity. Computational Fluid Dynamics (CFD) may be used to model and analyze these flow patterns, optimizing the design and placement of turbines to maximize energy capture.

Imagine you’re at the beach, watching waves crash. If you had a series of small windmills along the shore that were turned by the waves and tides, each time a wave hits or recedes, they would spin and produce energy.

We can use the no flow boundary condition. What are the boundary conditions we are imposing at the interface between air and waters? This is the interface between the air and waters that is what is the free surface boundary and what is the boundary conditions we are applying here.

Boundary conditions are crucial in fluid mechanics, especially in tidal energy systems. They define how fluid (water and air) interacts with structures (turbines or beds). The 'no flow boundary condition' means that at the bottom of the sea bed where the turbines are, no water will 'flow' through it; instead, the water will only move around it. Additionally, the conditions at the air-water interface (the free surface) must be carefully defined to understand the behavior of water as it interacts with air.

Consider the boundary of a swimming pool where water meets the pool edge. Imagine how the water behaves as you swim; vital here is that at the edge, water does not bypass the wall. This analogy helps understand how boundary conditions work in tidal energy systems.

We will not look it to solve this Navier-Stokes equations as it because it is a non-linear two-dimensional equations. We try to simplify these equations. That is what I will give you some of the examples how we can simplify these equations.

The Navier-Stokes equations describe how fluids move and are inherently complex due to their non-linear nature. In the context of tidal energy harvesting, it is often necessary to simplify these equations to make them more manageable for analysis. This might involve assumptions such as steady flow, incompressibility, and ignoring certain forces based on their insignificance compared to others.

Think of it like simplifying a recipe. If you're making a complex dish but only have a limited set of ingredients, you might decide to omit some steps or ingredients to make it easier and quicker to prepare. Similarly, simplifying equations helps us focus on the most important factors affecting tidal energy harvesting.

Always you can draw the velocities which is very interestingly here that if there is a interface and if I am to draw the velocity distributions the in air I will have a very fast the gradient to support these boundary conditions But in case of waters, we will have the less because this is what is 50 times lesser than that.

Understanding the velocity distributions at the interface of air and water is crucial for optimizing tidal energy systems. The disparity in velocity between water and air implies that different approaches may be needed for energy generation. For example, the greater resistance of water compared to air affects how effectively turbines can generate energy in tidal flows. As we advance, the understanding of these complex interactions will lead to improved designs for tidal energy harvesting systems and greater efficiency.

Imagine trying to blow up a balloon partially submerged in water. The resistance of the water makes it much harder to inflate in comparison to blowing air directly into the balloon above water. This analogy helps illustrate how different mediums interact and influence energy generation in tidal systems.

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