Hydrokinetic energy is an environmentally friendly source of electricity and it has the advantage to be more predictable compared to other renewables. According to IRENA (2020), the capacity of converting hydrokinetic energy into electricity is expected to increase in the coming decades as many concepts are in the pipeline. One of these hydrokinetic energy concepts is the patented Van Rompay Turbine. The Van Rompay Turbine consists of a duct, an air chamber and a paddlewheel. The duct, which is based on a Venturi working principle, consists of a converging inlet, a throat and a diverging outlet. Above the throat, an air chamber is present to provide an air environment to reduce resistance for the paddlewheel. The goal of this research was to experimentally and numerically test a prototype (L:4.05m x W:1.17m x H:1.17m) of the ducted system.Three inclination angles: 21°, 26° & 31°, for the converging inflow and diverging outflow segment were tested, referred to as the small, medium and large ramp size, respectively, to determine which size represents the lowest energy losses in the system. The small in -and outflow ramp represents the lowest energy losses compared to the medium and large ramp. Subsequently, on the small inflow ramp, five designs were tested, referred to as the straight, curved and the high, mid & low frequency waved designs; to again determine which design represents the lowest energy losses. Roughed waved wall designs are streamwise wavy walls with each a different wavelength and amplitude. The small ramp with a high, mid & low frequency waved design results in the lowest energy losses in comparison to the straight and curved designs for inlet velocities between 0 m/s and 0.4 m/s. For inlet velocities between 0.4 m/s and 0.5 m/s, the small ramp with a curved design represents the lowest energy losses in comparison to the straight and high, mid & low frequency waved designs.The data points acquired during the experiments were scattered due to external factors increasing the uncertainty of the measurements. Besides this, the experimental investigations were tested over an inlet velocity between 0 m/s and 0.5 m/s, limiting the data analysis. For this reason, several CFD simulations were carried out to acquire data with no influence of external factors and to investigate the system for higher velocities. The CFD simulations were executed for the five different inflow ramp designs with an in -and outflow inclination angle of 21°. The CFD model solves the Reynolds-averaged Navier–Stokes (RANS) equations with a k-epsilon turbulence closure model. Based on these CFD simulations, the best performing design for the inflow ramp in terms of the lowest energy losses for an inlet flow velocity between 0 m/s and 0.75 m/s is the high frequency waved design. Regarding velocities between 0.75 m/s and 3 m/s, the curved design represents thelowest energy losses compared to the straight and high, mid & low frequency waved designs. After scaling up the ducted system in CFD simulations with a factor 2 and 10, the flow velocity reduces as there are more energy losses in the system. However, as larger systems have a marginal lower specific surface of contact between the water and the duct, an increase in available flow power could be found. The extent to which the ducted system can be scaled up depends on the space restrictions at the specific location. Besides, the minimal required inflow area of the free water flow should be met. It can therefore be concluded that the potentially available energy for generation also depends the location where the Van Rompay will be deployed.Experiments need to be performed to study the hydrodynamic impact and the hydrodynamic efficiency of the paddlewheel to determine the power performance output and thus its potential value for the hydrokinetic energy market. It is recommended for future research to test the prototype at higher velocities and to test the prototype in a laboratory facility as these offer the benefits of controlled testing.

The current approach in the shipping industry by the use of highly toxic coating systems is harmful for our inland waterways and oceans, does not benefit the public health and is very undesirable for all aquatic organisms on our planet.
Almost every vessel today uses a toxic coating system which releases toxic compounds continually into our waterways and oceans. In this thesis a research is done to give an answer to the main question: ‘Is there an environmentally friendly and economically attractive coating for the shipping industry that deals with biofouling’.
The best approach examined by multiple criteria, is the use of a Hard, Inert Coating. Toxic compounds, like zinc anodes and copper, won’t be released into our waterways anymore. Therefore, the sediments of rivers and ports are better protected from pollution. Which will benefit the water quality and the public health.
The Hard, Inert Coating is the solution to prevent the NIS (non-indigenous species) problem. Because the vessel will be cleaned before leaving the port, no more marine organisms will be transported from their own ecosystem to another. Governments and port authorities will save a lot of money by preventing this problem.
Clean hulls will give less resistance and will save a lot of fuel consumption and improve its speed. Worldwide, the Hard, Inert Coating system could save $70.000.000.000 worldwide in one year. The sixteen largest ships in this world provide just as much pollution as 800 million cars. If you save 30 percent on fuel, it’s like you’re taking 240 million cars off the road.
As Hard, Inert Coatings are clean and do not emit harmful substances, more jobs in North- West Europe will be created. Currently, most ships go for repairs to dry docks in southern Europe and the Persian Gulf. Ruling on the use of toxic compounds are less observed here. By introducing a Hard, Inert Coating repainting is no longer required, and ships can be dry docked without any negative effects on the environment. In other words they can dry dock ”clean”. This will substantially increase the amount of work for ship repair yards in North- West Europe as owners do prefer these yards for technical and availability of service reasons.
The use of a 100% non-toxic coating to tackle the age-old problem of biofouling, will benefit the ecosystems all over the world. Different from the current situation, no more marine organisms will be polluted and killed. No more toxic chemicals will be released into the sediments of our ports, rivers and oceans. No more toxic substances will be absorbed by organisms and end up in our food chain. Our public health is continuously in danger by the fact that the toxic chemicals are released continuously day in day out.