The result is False in Darwin disigner

also you can see image of results

Hello,

I took a look at the model in the latest version of WaterGEMS, as well as the latest build of WaterGEMS V8i SELECTseries 4. There appears to be a discrepancy in the results you see in the model and the solution that already exists in Darwin Designer. I would need to know more about the steps you took to export the data from the Darwin Designer to the model to try to find out exactly what happened.

However, I exported the existing solution in Darwin Designer to a new scenario. When I did this and viewed the new scenario, the model looked far more reasonable, with only a handful of pipes seeing a change in diameter, including P-16 and P-20. These changes tended to be toward a smaller diameter pipe. I have attached a screenshot of what I see. I also recomputed the Designer run and saw the same results.

It is possible that the other solutions came from a different set of Options for the genetic algorithm. If you highlight the optimized run and select the Options tab, you can see the options available. Adjusting these can lead to a different set of results, which can sometimes yield a better solution. For that reason, new opitimized runs with a different set of Options can be recommended for some modeling cases.

Here is a TechNote on using Darwin Designer. There are also some tips in the Help documentation, under the topic "Advanced Darwin Designer Tips".

Regards,

Scott Kampa

Bentley Technical Support

Hello Ali,

When using the cost group "ali" you are allowing the pipes to be any size. I assume that is what you want to do.

Regarding the results, I believe that you simply need to run more trials. Currently, Darwin Designer is using all 50,000 trials. It may be that you simply need to try more. For instance, I highlighted the optimized run and then selected the Options tab. I changed Max Trials to 100,000 and recompute Darwin Calibrated. The exported results were improved. Note that this did not take more than a couple of seconds to compute on my machine, so you should be able to try even more trials without it taking too long to compute.

Basically, when you are seeing results that are unexpected or appear incorrect (and assuming that the input is correct), making adjustments to some of the Options can help. In a case like this, where the model was still looking for the most optimized result when reaching the maximum number of trials, increasing the number of trials can help. If the maximum number of generations is being met, you can try increasing that value. There is a lot of good information to be found in the "Advanced Darwin Designer Tips" section of the Help documentation.

Regards,

Scott

i had done what you said

but

in this conditions set for the range of velocity and pressure

not found in the results

Please show me the way to the specified conditions (velocity and pressure) in respect of the results

And diameters are obtained reasonable

from large to small diameter

tnx a lot

Hello Ali,

Based on your post, you are unable to get valid results for pressure and velocity when exporting results. After looking at some of the input for the Darwin Designer run, I believe what is happening is that the "Time from Start" selected is not a valid time. You are currently using 22 hours for the "Time from Start". However, at this time, there is no flow in the model based on the demand patterns (all demands are zero at this time). Because of this, the pipes are being undersized. When there is pump flow, you end up with high velocities and low pressures after computing the exported solution from Darwin Designer.

As a test, try setting "Time from Start" to 1 hour. Set the number of Max Trials to 100,000 and recompute the calibration study. Export these results and compute the model. Then use the Time Browser (Analysis > Time Browser) to look at the results for hour 1. The pressure and velocity results should be reasonable.

Some adjustment to the number of trials and other Options might still be needed for further optimization. Another good thing to try is to change the value for Random Seed, as this will give Darwin Designer a new starting point for the genetic algorithm.

In additon, engineering input will still be needed. In your model, the different patterns are impacting the results. For instance, negative pressures are still reported at various time steps for some nodes in the model. This appears to occur because there are no demands at hour 1 for these nodes and no flow in the pipes. For that reason, the pipes are actually being undersized by Darwin Designer. When there is flow through the pipes, the pressures drop due to headlosses in the pipe. You could see something similar for any time you choose.  

What you may need to do is pick a time when the pattern allows for flow in most pipes. For the pipes where there is zero flow, omit these from the optimized run by going to the Design Groups tab and unchecking the "Is Active?" cell. You may need to another optimized run at a second time to account for the other pipes. You will need to be careful about "Time from Start" that you use, as it will impact the results. .

Please let me know if you have any additional questions.

Regards,

Scott

hi Scott;

i think that Darwin Design is do calculation diameter for minimum flow

so it take minimum diameter from design group

you can see also DesignerSample2

we have negative pressure in result of optimization

so i think Darwin Designer not working for multiplier demand in 24 hour times

if i have mistake plz make my model that work correctly

tnx a lot

Hello Ali,

I am not seeing negative pressures in Darwin Designer n DesignerSample2.wtg. Are you making some adjustment to that model to see the negative pressures.

What Darwin Designer is trying to do is make the smallest pipe possible from the list of in the cost properties while still satisfying the pressure constraints assigned to the model. You need to start out with good pressure data and a good start time for the Designer run. In your model, you were looking at a case where the demands and flows in your system were zero. This was causing the pipes to be too small when there were demands in the system.

I would suggest looking at the two Darwin Designer Quick Start Lessons found under the Help pulldown menu (Help > Quick Start Lessons). This may give you a good idea o the workflow and what the results will look like.

Regards,

Scott

Hello Ali,

I am not seeing negative pressures in Darwin Designer n DesignerSample2.wtg. Are you making some adjustment to that model to see the negative pressures.

What Darwin Designer is trying to do is make the smallest pipe possible from the list of in the cost properties while still satisfying the pressure constraints assigned to the model. You need to start out with good pressure data and a good start time for the Designer run. In your model, you were looking at a case where the demands and flows in your system were zero. This was causing the pipes to be too small when there were demands in the system.

I would suggest looking at the two Darwin Designer Quick Start Lessons found under the Help pulldown menu (Help > Quick Start Lessons). This may give you a good idea o the workflow and what the results will look like.

Regards,

Scott