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From 1997-12-01 till 2000-03-07 we measured wind, rain and driving rain in full scale at the TUE site. In Driving rain on building envelopes (Technische Universiteit Eindhoven, 2002), Fabien J.R. van Mook reported the description of the measurement set-up, analyses of the data and the comparison of the measurements with CFD simulations of wind and driving rain at the same site. This report can be downloaded in PDF-format (2857 kbytes) or can be read on-line in HTML. The measured data is available via a link below.
A short description with primarily pictures is found at the page measurementsetup.html.
Driving rain is rain that is carried by the wind and driven onto the building envelope (façades and roofs). It is a complex phenomenon of falling raindrops in a turbulent flow of wind around a building. It is one of the important climatological factors which determine long-term use and durability of building envelopes.
We started the present study because the adequacy of the measurement techniques for driving rain described in the literature (from 1937 onwards) was doubted, and because, since the beginning of the 1990s, computational fluid dynamics made simulations of the complex phenomenon of driving rain --and hence a better understanding of it-- possible.
We developed a driving rain gauge which we improved by addition of a turning wiper. We tested it in an international comparison experiment in full-scale on the west façade of the Main Building of the Eindhoven University of Technology. The results indicated that our improved driving rain gauge is an accurate and reliable instrument, and that one may measure approximately half of the actual driving rain amount by an unimproved, traditional driving rain gauge. We formulated design rules for driving rain gauges.
The full-scale experiments resulted in a unique series of continuous wind, rain and driving rain measurements during 24 months. Raindrop spectra with a disdrometer were measured during 3 months too. The measurements are detailed (data at 5-minute intervals were provided) and are available for future research.
The measurements of driving rain on the west façade of the Main Building showed much variation for all observed reference wind and rain quantities. A traditional empirical model (Lacy 1965) was applied to the data. We presented an improved empirical model, by which wind direction and position on the façade are explicitly taken into account. Only with the improved model we could estimate quite accurate values of maximum driving rain intensities.
The wind at the experiment site was simulated by a standard K-epsilon model, and the results compared well with the measurements. The applied model of driving rain takes drop trajectories (including the drop dispersion due to wind turbulence) and raindrop spectra into account. The simulated driving rain intensities on the two positions on the west façade compared rather well with our measurements of driving rain. We discussed the aspects which should be dealt with to obtain reliable simulation results.
Keywords: building envelope, façade, durability, micro-climate, wind, rain, driving rain (= wind-driven rain), raindrop spectrum (= raindrop (size) distribution), driving rain gauge, computational fluid dynamics (= CFD), standard K-epsilon model.
The data measured at our site are available for download in one huge compressed file of 48.417 kbytes (obtained with the unix utility tar). Uncompressed it will take 267.792 kbytes. After uncompressing one can read the instructions in the file info/manual.htm with your HTML-browser. For your convenience, you can read this file also on-line now.
A short message to prof.dr.ir. Martin H. de Wit <M.H.d.Wit@bwk.tue.nl> is appreciated when you use the data for simulations, comparisons, driving rain models etc. See his complete address below:
For questions and remarks one can contact prof.dr.ir. Martin H. de Wit. His address is:
Martin H. de Wit
Building Physics group (FAGO)
Technische Universiteit Eindhoven
Postbus 513
NL-5600 MB Eindhoven
the Netherlands
Telephone: +31-40-2472557
Fax: +31-40-2438595
E-mail: M.H.d.Wit@bwk.tue.nl
Or one may contact Fabien J.R. van Mook:
Fabien J.R. van Mook
Building Physics group (FAGO)
Technische Universiteit Eindhoven
Postbus 513
NL-5600 MB Eindhoven
the Netherlands
E-mail: F.J.R.v.Mook@bwk.tue.nl
Fabien J.R. van Mook, Martin H. de Wit & Jacob A. Wisse, Computer simulation of driving rain on building Envelopes, Proceedings of the 2nd European and African Conference on Wind Engineering, Genova, 22-26 June 1997, pp. 1059-1066 (PDF-file: 108 kbyte)
Fabien J.R. van Mook, Description of the measurement set-up for wind and driving rain at the TUE, internal report FAGO 98.04.K, March 1998, Eindhoven University of Technology (PDF-file: 1509 kbyte)
Fabien J.R. van Mook, Measurements of driving rain by a driving-rain gauge with a wiper, Paper presented at CIB taskgroup 21 meeting, Gävle (SE), 5/6 June, 1998 (PDF-file: 504 kbyte)
Fabien J.R. van Mook, Measurements of driving rain by a new gauge with a wiper, internal report FAGO 98.62.K, June 1999, Eindhoven University of Technology (PDF-file: 467 kbyte)
Fabien J.R. van Mook, Full-scale measurements and numeric simulation of driving rain on a building fasade, Wind engineering into the 21st century: Proceedings of the 10th International Conference on Wind Engineering, København (DK), 21-24 June 1999, p. 1145-1152 (PDF-file: 442 kbyte)
Anneli Högberg, Mikkel Kragh and Fabien van Mook, A comparison of driving rain measurements with different gauges, Proceedings of the 5th Symposium of Building Physics in the Nordic Countries, Göteborg (SE), 24-26 August 1999, p. 361-368 (PDF-file: 247 kbyte)
Fabien van Mook, Measurements and simulations of driving rain on the Main Building of the TUE, Proceedings of the 5th Symposium of Building Physics in the Nordic Countries, Göteborg (SE), 24-26 August 1999, p. 377-384 (PDF-file: 355 kbyte)
Fabien J.R. van Mook, Driving rain on building envelopes, Ph. D. thesis, Technische Universiteit Eindhoven, 2002 (PDF-file: 2857 kbyte; on-line in HTML)
Within the Eindhoven University of Technology (TUE), we collaborated with the group of Measurement and Computer Science (now: the Magnetic Resonance Laboratories) of the faculty of Technical Physics. The research project was supported by the common TUE commission on «Technology for Sustainable Development» (TDO).
Internationally we collaborated with:
In April 2000 we carried out wind tunnel experiments with our collegues Bert Blocken and prof. Carl-Eric Hagentoft (Chalmers University) for measurements of wind and driving rain in the Jules Verne Climatic Wind Tunnel of the Centre Scientifique et Technique du Bâtiment in Nantes, France.
Searching for «driving rain» with Google, we found some 18,300 links (October 2000). We selected the following links from the first 500 links found, although for a better overview one should also look for synonyms and non-english equivalents. Here you find our uncommented selection:
URL of this page is: http://sts.bwk.tue.nl/drivingrain/
© 2002-2003 Technische Universiteit Eindhoven/ Fysische Aspekten van de Gebouwde Omgeving
First publication: 13 December 2002.
Last update: 12 June 2003.