[Suitable Measurement height for Wasp Calculation]

Hi wasp team,

If i have a mast take measurement at 80meters height and 100meters height , and the predicted turbine hub height is 80 m ,which measurement height is appropriate to use for WAsP calculation ?

thanks .

[61400-12 Annex B flow model validation]

Hi

you can go to wasp home to download the software called WAT (wind park assessment tools ) it can help you to test the terrain according to IEC to decide whether a site callibration or a flow modelling is needed for the PCV .

a wasp engineering installasion was needed for this process .

[sectorwise frequencies in lib file]

regarding the change of direction due to roughness , would you provide more detail when you find this ? i think the direction change should be induced by terrain not roughness.

[sectorwise frequencies in lib file]

hi pdoubrawa ,

the height is actually a group ,which normally with default settings of 10m 25m 50m 80m 200m , this group called atlas , which is calculated base on your measured height and your other inputs , you can change the default height to match your hub height to reduce the uncertainty of interpolation.

[Extract of Histogram at predicted site]

Hi mark ,

thanks for your reply , yes i have try to increase the sector number try to get one bump weibull at the dominant wind direction , but even with 36 sectors it was still bimodal at the dominant wind direction , so i am wondering if can get the corrected wind speed histogram at turbine site but not the fitted weibull .is that possible to get this in wasp ?

Thanks in advance .

[Extract of Histogram at predicted site]

Hi wasp team ,

is that the flow modelling correction of wasp was down on a sectorwise wind speed histogram level base on the measured data?
i just saw from the European atlas , it described in the application process seems the correction is made on the wind speed hitogram ,bin by bin .
if so , is there any way to extract the histogram at each site , for some cases which bimodal weilbull appeared , if can get the histogram use for aep without fiiting weibull i think the percertage of error could be lower .

Thanks in advance .

[Parameter : Sub-sectors in roughness map analysis]

Hi rathmann,

thanks for your reply .

as my understand the distance ranges you mentioned (e.g. 0-500m, 500-2300m, 2300-7000m ) should be the roughness length change line right ?

and there is another parameter called : "Max. number of roughness changes/sector"
the default value is 10 , and i think this parameter defines the same rule as you explaination for"Sub-sectors in roughness map analysis" ,then i am confused what is the difference between the two parameters here ?

thank you.

[Developer lisence]

Hi wasp experts ,

my company want to purchase a developer lisence of wasp to carry out some tests .

i want to konw how much is it .

Thanks.

[Parameter : Sub-sectors in roughness map analysis]

Hi wasp experts ,

would you help to explain what is the wasp parameter "Sub-sectors in roughness map analysis" mean ?

how will it effect the roughness rose ?

[BIMODAL wind distribuition]

Hi ,

you are welcome .

i have not see such trick issue before , i think your idea is worth to try. and i saw that you mentioned the site is flat right ?if the terrain feature and roughness not variaed much at the NNE ,then i have an idea that may be we can add a for example 10 degree of direction offset to one set of seasonality effected wind data ,and then you can seperate the bimodal by increase the sector numbers , if the terrain and roughness not changed a lot within these few tens of degrees then the deviation of aep would be very small .what is your opinion to this ?

[BIMODAL wind distribuition]

Hi ,

just one assumption , that have you try to increase the sector number to see the sectorwise fitted distribution ? i think for those special climate with strong seasonality the wind direction sould be some kind of variation with season change , and since wasp use sectorwise weibull for AEP calculation and if we can store different wind into different sector and then may still can get a well fitted sectorwise weibull .and this won't change the AEP ,although the overall fiting looks bimodal .

[Decide location of Roughnees change line from sea to land at seaside]

Hi wasp expert,

i am comparing wasp predicted profile at mast location with measured profile at

several costal projects , to search for a rule of thumb to decide the location

of roughness change line from sea to land . i find six projects , all masts have

a distance to sea around hundrads of meters . all 6 sites with very flat

terrain , and roughness length change is low no forests , no obstacles. if i

locate the sea-land roughness line according to the reality,( means the mast is

located within land area about hundards meters away from sealand roughness

change line ) than all 6 six predicted profile is very bad , with only one

intersection point with the measured profile indicate only self point prediction

is ok .( mast measurement height 30m 50m 70m/80m use the highest level for

calculation full year data )but if i extend the sea-land roughness change line

to cover the mast ( mast within sea area hundards meters to the roughness change

line ) than all 6 predicted profile get a obivious improvement .(due to low

roughness length change from sea to land 0.00~0.0x , the effect of IBL model can

be neglect i think )measured and predict profile very alligned from 30~90m at

all masts .do we have any rule of thumb already for determine the sea land

roughness change line ?

Thanks in advance !