Well discretisation

Hello. I would like to simulate the water level inside a pumping well as exactly as possible using a multi layer well.

I know FeFlow now has a couple of attributes of the multi layer well that are supposed to help me in doing this, i.e. Ideal element size, virtual radius But i cant find the explanation behind these attributes.

What exactly is "virtual radius" and "Ideal element size" ?.

It seems that ideal element size in my case is quite large (> 1m)  compared to my discretisation around my wells. Is this a problem ? or is it only a problem when cell sizes are smaller than actual radius of the well ?


Christian

When cell sizes are below the ideal radius, the drawdown shown in the model well will be larger than realistic (pumping well). If cellsizes are larger than the ideal radius, calculated heads will be higher than realistic.

Thanks for the reply Peter. Is it correctly understood that the flow into nodes simulating wells with fixed head is then also depending on the cell size ? So that the flow is underestimated when the cell size is too small ?.
And what does this mean for other nodes with a fixed head, model bundary conditions etc.  ? I suppose that only when there is a high gradient is the error large ?.

I think this is only a problem for wells because they are so spatially discrete, compared to say a river or water body, which exist over multiple nodes.