We've added the KCA series to the open-water solver. It includes the cavitation effects on the thrust and torque. A polynomial formulation is used for estimation of the relevant coefficients according to the following reference:
Radojcic, D. An engineering approach to predicting the hydrodynamic performance of planing craft using computer techniques. Transactions of the Royal Institution of Naval Architects, Vol. 133, 1991, pp. 251–267.
A paper about the novel method has been published in a Q1 journal, Ocean Engineering. You can read the full text here. The paper went under a rigorous peer review, through which we have enhanced the method even more. Their feedback is greatly appreciated! The next step is to publish a validation study on our trim and sinkage solver.
Transom effect on a) wave-making b) viscous pressure resistance
The trim and sinkage solver separately assumes the pressure distribution from wave-making and local flow. At the moment, local flow is approximated based on this, which is crude, but still okay for an approximate guess for (semi-)displacement ships. The method that includes transom effects on wave-making is a novelty, more info soon.
This is a development version, please keep that in mind, and expect more updates soon! At the moment there are > 80 active users that occasionally do calculations. Thanks to those that gave me feedback!
If one looks at e.g. the Wide-light validation example, the trendline of trim and sinkage is nicely predicted. So reaching Froude numbers 1.0 is now not a problem, along with including an immersed transom on higher speeds, which significantly affects wave-making. Furthermore, this hull form is far from slender forms, it's a huge improvement that the modified thin-ship theory can handle it.
We've started the journey with the novel hull resistance solver, which soon will be enriched by adding a solver for the dynamic equilibrium (trim and sinkage). This will be the fastest validated CFD solver for vessels, that is also runnable inside the browser.
In between tests of the equilibrium solver, we're going to add already tested propulsion calculators. The first in the row is the Wageningen B-seriescalculator, which dynamically outputs the characteristics. Next follows Gawn, KCA, and optimizers.
By the way, we get a lot of feedback concerning the resistance. Please feel free to share your ideas and wishes for the propulsion, seakeeping, etc.!
Now the resistance calculator more accurately implements the boundary layer and wake effects on the wave resistance. In addition, we've added the initial implementation for demihulls! Please see the changelog.
Coming soon: Rhino plug-in, dynamic trim and sinkage to reach high displacement speeds, and then planing speeds!
The initial version of the resistance calculator is now added to the website. The calculator is applicable for most types of ship hulls that sail in the displacement mode, without deeply immersed transoms.
For the prediction of ship resistance in the preliminary stages of the ship design process, naval architects often use methods that are less complex and expensive than CFD simulations and experiments. Michell's thin ship theory can be used to quickly evaluate wave-making resistance, although, the original theory gives poor estimates for conventional hulls. In this calculator, techniques to improve the theory are introduced that account for viscous and non-linear effects. The improvements are validated by numerical simulation on profoundly different hull forms.
The website is being set-up as a skeleton for adding various content, i.e. the website will provide easy, quick and user-friendly access to a large quantity of tools for naval architects and marine engineers.
This website is not a static site: it is continuously updated and checked for quality. User suggestions and requests are welcome. Our team is going to answer the suggestions and submit them to evaluation. You can contact us by using the contact form.