Morten

Hi Marcos, There is no export to file option for the 'Windfarm overview' results, but you can copy text to clipboard and then paste it into another program. This is done by clicking somewhere in the table you want to copy and then press Ctrl+C on the keyboard. The columns are separated by TAB characters, which works well with MS Excel. In MS Word the imported data will first appear as text, but you can select all of it and then convert it by selecting 'Insert>Table>Convert Text To Table...' and remember to set a checkmark at 'Seperate Text as TABS'. Cheers, Morten

The Coriolis parameter is proportional to sin(lat) - thus highest with opposite signs at the two hemispheres and zero at the equator. WAsP Engineering applies this parameter for conversions between 'observed', 'geostrophic' and 'generalized' winds, using the so-called geostrophic drag law. In contrast, the longitude is not used in the model.

Hi Gyeongil, Sometimes you can use an error messages to guess what is wrong, but in many cases it is mainly useful for the programmer. The auto-generated text lines are associated with exceptions in the code, i.e. unexpected events which disturbs your calculation in various ways. You often see a chain of exceptions caused by a number of routines calling each other. When you report a problem to WAsP support (using 'Help| Email technical support') it is usually a good idea to copy-paste the error message into your email describing the problem. Another useful approach is to include some test data enabling the programmer to reproduce the problem. Cheers, Morten

The Excel-based layout tool is now awailable at http://www.wasp.dk/dataandtools#wasp-tools__wind-farm-layout-tool

Hi Guido, The uncertainty causes and there estimates are nearly arbitrary and just shown for inspiration. You should try make new estimates for each project, and ideally these should be based on statistical data. Some are easy to find, e.g. the accuracy of anemometers which can be read from instrument manuals or wind-tunnel calibrations test. My colleague Mark Kelly is working on error estimates for flow modelling in WAsP, e.g. on the vertical extrapolation, see http://www.wasp.dk/news/nyhed?id=A7044C06-6F5A-4806-8BFD-97CB44A7F112. Other estimates, like uncertainty related to turbine availability, can be harder to find. For this you need access to data from similar project and consider the maintenance strategy, e.g. what is the service plan, limitation on the site access, access to spare parts etc. With best regards, Morten

You could try to reduce the memory usage following the Fuga help file section 'Further information>Fuga speed and memory usage'. The most important tip is that Fuga consider turbines with different hub heights as distinct turbine types, so it is a bad idea to specify individual hub height if these are on the order of a few centimeters.

This is a known bug in a routine gauging the memory use. It is a simple integer overflow and may happen even though you still have not used all the RAM memory. I already fixed it in the developer version.

Hi Clanker, If you select the single-wake page and display a crosswind profile of the velocity deficit you will usually see some undulations outside the main wake. A slight deficit (actully a speedup) next to the wake might be realistic, but it is hard to believe such effects further away so we think that the undulations are caused by a numerical problem in the progam. This undeciered 'model feature' might explain small errors in sector-wise AEP results. You are welcome to send a test case to WAsP support if you see errors are significant and suspect that something else might be wrong. Cheers, Morten

Hi Nico, I am not quite sure which correction you refer to, but I think the answer must be no. You might adapt wind turbine power curves to local turbulence conditions, but WAsP has no built-in method for this, so you would have to do it externally and use the same power curve for all wind directions. Furthermore, the turbulence predictions are only included in WAsP-CFD, not the traditional IBZ WAsP flow model. Best regards, Morten

Hi vman, A turbine with an IEC classification is strong enough to survive a set of design load cases defined in the IEC standard. The environmental conditions for these load cases are modelled by relatvely simple model scaled by reference velocity, Vref, and reference turbulence intensity, Iref. Thus, a turbine with high Iref is tested by more severe turbulence conditions than one with a low Iref. One of these models is called the normal turbulence model (NTM). It is not a fixed turbulence level but something which depends on wind speed. The IEC standard does not classify the sites, but does have a site assessment procedure. The main principle is that the local conditions must not exceed the conditions assumed in the load cases used for turbine classification. There are several checks to be made. For turbulence we must check that the 90% level of the scattered distribution of turbulence conditions (including wake effects and depending on wind speed) must not exceed the NTM model (however only in a certain wind speed range). There is more information in the WAT help file and the most precise description is of course the IEC 61400-1 standard. Cheers, Morten

Hi Cunhae, WAT is trying to support the terrain assessments in IEC 61400-1, IEC 61400-12-1 and IEC 61400-12-2 and they are all different. Furthermore, there are variations among different editions of these standards, and sometimes it is not always clear how to interpret them. When you say maximum slope and variation, I assume that your question refers to IEC 61400-1. First thing to notice is that according to editions 2 and 3 (but not the coming edition 4) the fitted planes must be forced through the tower base. The WAT help file will tell you how this is done in WAT by a least-square-error minimization. Two alternative sets of reference points can be used: 1) all points in the orthogonal grid map lying inside the segments or 2) new points interpolated to a polar grid. I recomend the first method for high-resolution maps and the second method (interpolation) for low-resolution maps. The fit will generally have a tangential component unless you select the option called 'force slope of fitted plane along sector centreline'. The standard does not specify whether this is needed or not, so I found it best to make it optional. Edition 2 (1999) and the original edition 3 (2005) defined the variation as the maximum distance between the fitted plane and auxilary planes fitted to a small disc at every point of terrain assessment. I suppose the intention was to filter out effect of small terrain features. The rules changed in the ammended edition 3/A1 (2010) so now we check the vertical variation at all points, but only consider the criteria to be failed when exceedance is found for points corresponding to an area larger than 5*sqr(z_hub). The WAT project options will allow you to decide whether you want to calculate the variation as specified in the ammendment or not. I admit that this can be confusing. There are many options to consider, so please consult the WAT help file and the edition of the IEC standard you want to follow. You can also right-click the root element in the WAT object hierarchy and open the project option window, then you can select file>default option for the relevant edition. Best regards, Morten Nielsen

Hello, You need an input file for the wind turbine generator you want to use in your project. The first step is to estimate the average air density for the site, e.g. by the air density calculator under the 'tools' menu in WAsP. Next step is to contact the manufacturer and ask for a power curve and thrust coefficient curve for the turbine operating at the given air density. If they dont supply these data in WAsP format, you launch the WAsP Turbine Editor, also found under the 'tools' menu, type in the turbine information and export the data to the file which can be used in WAsP. With best regards, Morten

Hi, Ct means thrust coefficient and it is defined by the thrust force normaliced by the rotor-swept are, air density and wind speed. It is a function of wind speed and needed for the wake model. You can usually get it from the manufacturere. At the moment the wake model of WAsP only supports horizontal-axis turbines. Regards, Morten

Hi Sinisa, There is no radius involved in these calculations. The terrain elevation grid map is Fourier transformed as input to the flow model which is formulated in Fourier space. A computationally efficient way to calculate terrain gradients is to multiply each Fourier mode by wave number vectors and then find the gradient map by inverse Fourier transformation. Values for specific sites are found by interpolation in this grid map. The flow inclination angle are found as the angle between the vertical and horizontal wind components and it approaches the terrain slope close to the ground. You are right that in general the flow inclination angle should decay in the vertical direction, but there can be local exceptions. The reason is that flow perturbations caused by small terrain features decay faster in the vertical direction that perturbations caused by large terrain features. There is a slide from our WEng course showing this and you can download it from http://wasptechnical.dk/Services/Redirect.aspx?token=8c8d0b3b-769d-4b4f-89aa-6e09aa4cca2b Cheers, Morten

Hi Eduardo, First thing to check is that the format of the first column is set to time and not text. Try to select all cells in the first column except the header. Then right click a cells in the selection, select 'Format cells' from the popup menu, and pick a 'Time' format of your own choice. If this does not help, you are also welcome to send us a test file to our help desk using the e-mail link under 'help' in the WAT main menu. I just remember one more thing which is that your PC must have an Excel installation. Currently WAT is not interpreting the Excel file but launcing Excel and using it to read the data. You should also close the file in Excel while trying to read it in WAT, as otherwise it will be blocked for reading. If this becomes a problem for many users, I should find another solution for a future WAT version. Cheers, Morten

Happy New Year to you too! The best practice is to use an OWC based on observed time series with no prior correction for height differences. WAsP models speedup effects between anemometer positions and turbine nacelle positions and this both includes horizontal and vertical variation. There is a document on WAsP best practice available for download at http://www.wasp.dk/Support-and-services/FAQ#webhelp

Hi Trubert, The format of the WAsP WRG file is explained in the WAsP help file section 'Technical refference| WAsP file formats| Resources grid'. The first line describes the grid layout and the folling lines are data records for each grid point. They have the format - Text string (10 characters) identifying the site/grid point - X-coordinate (easting) of the site [m] - Y-coordinate (northing) of the site [m] - Z-coordinate (elevation) of the site [m] - Height above ground level [m a.g.l.] - Weibull A-parameter for the total distribution [ms-1] - Weibull k-parameter for the total distribution - Power density [Wm-2] or power production [Why-1] - Number of sectors - Frequency of occurrence for sector #1 [%·10] - Weibull A-parameter for sector #1 [ms-1·10] - Weibull k-parameter for sector #1 [·100] - Frequency of occurrence for sector #2 [%·10] - Weibull A-parameter for sector #2 [ms-1·10] - Weibull k-parameter for sector #2 [·100] and so on for all sectors. Your mean wind speeds are suspiciously high, i.e. 14.3 m/s in general and 22.0 m/s in sector 8, according to my check. So you should go back to your WAsP (or WindFarmer?) project and check if there is something wrong. Regards, Morten

Hi Aitor, I was referring to our IEC turbulence simulator, which you can download from http://www.wasp.dk/Software/WAsP-Engineering/IEC-Turbulence-Simulator It is like the software you have with a Windows user interface on top of it. You can choose between the same three spectra as in WAsP engineering - see the table at the top of page 2 in ComspecManual.pdf Best regards, Morten Nielsen

Hi Aitor, Comspec and Windsimu are two programs made prior to the Turbulence Simulator. Their use are described in two PDFs normally shiped with the software (not really part of WAsP Engineering). I can mail them you if you write to our user support system. They do not attempt to simulate a coherent gust, but the simulated turbulence has realistic coherence. Best regards, Morten Nielsen

Hi Erkan, The WAsP Map Editor offers several possibilities. 1. You may by press ‘Edit| Clip Map| Map part’, define a rectangular or elliptical boundary, and then decide to keep either the map part inside or outside the boundary. 2. When you combine two maps you can either use the ‘File| Add’ or ‘File| Add and Replace’ methods. If you chose 'Add and Replace' the contours from an already loaded map will be deleted in the area covered by the new map. This is a good way to avoid crossing contours from two maps, e.g. maps with coarse and fine resolution. 3. It is sometimes practical to remove all contours of a certain type. This is done by pressing ‘Edit| Clip Map| Contour/line Attributes’ and then select from the emerging popup menu. This way you could for instance remove all height contours from a map before you replace them with height contours from a better map and avoid losing your roughness contours. Find more information the the Map Editor helpfile. Regards, Morten

Hi Nicolas, I just made an answer on the support help desk to someone who might be a colleague of yours. Anyway, the question is fairly general, so I see no confidentially problem in repeating the answer here. It goes like this... "If your goal is to see the AEP of a reduced windfarm layout containing only every second turbine of the turbines in your present project, then the easiest way is to split the turbine group into two groups. You can then temporarily drag the turbines you don't want to include in the calculation outside the WAsP project, to the root level of the workspace object hierarchy, and repeat the calculations for the reduced wind farm. When you want to see the AEP of all the turbines you drag the turbine group back into the project. Maybe this is not exactly what you need. Wind-farm operators sometimes use a strategy where some turbines are shut-down for certain wind directions to avoid excessive wake loads from neighboring turbines. This strategy is often referred to as sector management. Unfortunately, it is not yet supported in WAsP. We do however have a Windfarm Assessment Tool (WAT) which can make this calculation in an approximate way. You can read about this at http://www.wasp.dk/Software/WAT. You need WAsP Engineering to generate input to WAT, as one of its main features is to do IEC site assessment (extreme winds, turbulence, shear and flow inclination angles)." Best regards, Morten

First you export your data as an ASCII file and import these into the WAsP Climate Analyst wher you create a Observed Mean Wind Climate (OMWC) and store this on file. Now go to WAsP, create a generalized wind climate, specify the met mast position and provide access to the OMWC file. You need a map for the terrain data in your WAsP project even if it is totally flat with uniform surface roughness. You can create such maps with the WAsP Map Editor. After these preparations you will be able to insert turbine sites in the WAsP project and predict the wind climates for these. I recommend that you read the 'step-by-step example' in the 'guided tour' section of the WAsP help file. We also have WAsP training courses.

WAT imports the mean wind climates of WAsP. I will only make short comment here and refer to the WAsP help file, similar questions in the WAsP section of this forum, and the European Wind Atlas for detailed information. A1 WAsP fits the PDFs by matching two statistics of the observations with the Weibull probablity distribution. These statistics are the average cube of the wind speed and the probability of winds above the empirical mean wind speed. This usually gives a good fit in the upper part of the wind distributions which is most important for the power production. NB: The mean wind speed of the Weibull fit will not match the data perfectly. A2 The extrapolation is done with the WAsP model. There is no simple formula. A3 Please read about roughness classification in the help file of WAsP, the help file of the WAsP Map Editor and the European Wind Atlas. Cheers, Morten

Hi GianLuca, Nice work! I am already speculating whether our university students could do similar sensitivity studies by scripts, e.g. as part of their master theses. Cheers, Morten

Hi Gianluca, Good to hear that you are making progress. I don't know enough to help you with the new problem, but one of the expert has promised to post a hint. Best regards, Morten