# MeasureTool - Wave gauge during or after wave breaking

Dear all,

I have a query on how wave gauges measures values during or after wave breaking?

I appreciate the information given on MeasureTool. Please check that here - https://github.com/DualSPHysics/DualSPHysics/wiki/5.-Running-DualSPHysics#563-analysis-of-numerical-measurements-measuretool

A simple explanation on how measuretool works is given by the following line from the document and the figure -

"Note that MeasureTool is looking for the Z-position where there is a change between fluid and void, starting from the lower point defined in POINTSLIST, i.e. BeginZ, and moving upwards. It stops when the nodal oint is higher than a given reference mass."

But What would happen if there is a wave breaking? This could lead to small void at the top of the surface. It will have more than one intersection of void and fluid along the z - direction.

Thanks

• Have you tried to produce a breaking wave and then trying to retrieve what it measures?

If there is a wave breaking it will probably select the value closest to m = 0.5*m_reference and report that, whether or not that is at sea surface or at wave breaking elevation.

It will probably not work as you want if you are using gauges.

Instead you could use measure tool with a grid and then in post-processing assessing where a wave broke based on the m value calculated at each grid point.

Then you could expand on that your self later, through another layer of programming, to plot it is a function of time.

Kind regards

• New v5.2 to be release in May 2023 will include options to deal with this since you can compute surface elevation of the tip of the wave during breaking, so that finding free surface from the top and from the bottom.

Regards

• Thank you so much @Alex for this update. I am looking foreword for this new version!

Thanks @Asalih3d for possible solution. This could be an interesting to look at. Could you please explain what do you mean by use of measure tool with a grid?

• In a 2D simulation you make a 2D grid of points at which you measure the density or something else of the water. If density is present, it means water is present, if not otherwise. Then you can post-process this grid to extract height as you want

Kind regards

• Oh got it. That's an interesting approach. Thanks @Asalih3d!