CFD (Computational Fluid Dynamics) simulation software provides many advantages as a replacement and enhancer of real world testing. However, using CFD for product development and prototyping isn’t always feasible. Due to the inefficiencies of legacy solvers, CFD wasn’t always an option. Envenio is hoping to change this with their solver that reduces the cost and time associated with CFD simulations, enabling the use of CFD in a wide variety of new applications. This article investigates its practical and cost-effective use in tidal site development.
The real world test in this article is ADCP, a hydro acoustic current meter which measures water current velocities over a depth range. The test uses the Doppler effect of sound waves, that are scattered back from particles within the water column.
USING CFD AS AN INITIAL ASSESSMENT
In this example, ADCPs are deployed in numerous quantities across a large area, with the ultimate aim of finding the most suitable site. This can be expensive, time consuming and result in a large amount of wasted deployments, as many of the areas prove to be unsuitable.
For this reason, CFD can be used in the initial assessment stage before such ADCPs are even deployed. There are huge cost and time efficiencies here, and CFD’s ability to look at many sites at the same time, as well as providing a better understanding of the overall site characteristics, makes it advantageous.
When used as an initial assessment in this particular field, a key deliverable is the ability to produce turbulence intensity maps. These are critical to device loading and survivability. In addition, CFD software simulations highlight recirculation zones and stream wise vortices, in other words, the presence of unsteady effects, further enabling a suitable site choice to be made.
It is this ability to provide 'intelligence' that makes CFD analysis so relevant at the initial assessment stage.
USING CFD AS AN ENHANCER
While using CFD before ADCPs are deployed is arguably the most productive choice, it can still provide benefits when used during or after their deployment.
Overall, CFD can add value to the measurements acquired by ADCPs, simulations are validated and a greater confidence in the data provided can be had.
COST-EFFICIENT & TIME EFFICIENT
In this example, a number of ADCPs would usually have to be deployed to multiple sites in the search for the best site. With each ADCP costing in the region of $40,000 - $80,000, this is by no means a cost-effective method, and results in a number of wasted deployments. The use of CFD means that through its simulations, deployments of ADCPs can be less frequent and more targeted. A CFD simulation that gives information on multiple sites is only between $25,000 -$35,000 (an internally run model cost would be even less).
CFD also provides a considerable time-saving advantage. Each ADCP deployment lasts around one month, and the results can take a further three months to process. With certain ocean conditions required for ADCP deployment, the time of year also has influence, neither of which affect CFD. A comparable CFD run including multiple locations only takes one to two months.
COMBINING CFD AND PHYSICAL TESTING
Using CFD along with ADCP can achieve great success. Both Open Hydro and DP Energy have used Envenio simulations in conjunction with their ADCP deployment, gaining a better understanding of the sites in which they were working and making accurate, cost-efficient decisions as a result.
Used together, a larger picture of the area can be captured and the most financially and practically beneficial site selection can be made.
The use of CFD and ADCP together could also prove useful for any project where flow or current information needs to be accumulated, for example, when building off shore structures.
For those looking to investors, anything that reduces project risk, and increases accuracy and profitability, has to be looked upon favorably. Tidal energy is riskier than other forms of clean energy, so can often scare away investors. The information provided by CFD simulations can ease such fears, and reduce risk. CFD can now be considered as a preliminary step before running a pilot experiment. Testing scope flexibility, timeliness, and visualization give product developers a much higher caliber understanding of how their device will perform.
Envenio's CFD solver outperforms many other commercial HPC solutions, meaning that using CFD as a replacement or enhancement to real world testing is not only more accessible, but more affordable. The cost savings are vast, with some tenfold reduction when compared to other solvers. To read more about our demo cases, go to this page.
If you'd like to learn more about the basics of getting started with CFD, check out our Essential Guide to CFD Simulations.