Modelling the atmospheric dispersion of radiotracers in small-scale, controlled detonations: validation of dispersion models using field test data

A series of modelling exercises, based on field tests conducted in the Czech Republic, were carried out by the ‘Urban’ Working Groups as part of the International Atomic Energy Agency’s Environmental Modelling for Radiation Safety II, Modelling and Data for Radiological Impact Assessment (MODARIA) I and MODARIA II international data compilation and model validation programmes. In the first two of these programmes, data from a series of field tests involving dispersion of a radiotracer, 99mTc, from small-scale, controlled detonations were used in a comparison of model predictions with field measurements of deposition. In the third programme, data from a similar field test, involving dispersion of 140La instead of 99mTc, were used. Use of longer-lived 140La as a radiotracer allowed a greater number of measurements to be made over a greater distance from the dispersion point and in more directions than was possible for the earlier tests involving shorter-lived 99mTc. The modelling exercises included both intercomparison of model predictions from several participants and comparison of model predictions with the measured data. Several models (HotSpot, LASAIR, ADDAM/CSA-ERM, plus some research models) were used in the comparisons, which demonstrated the challenges of modelling dispersion of radionuclides from detonations and the need for appropriate meteorological measurements

Application of Pressure Sensitive Paint -Theory and Practice-

For investigations of pressure distributions on wind tunnel model surfaces with high spatial resolution new experimental techniques, such as Pressure Sensitive Paint (PSP) are required. Using this non- intrusive optical pressure measurement technique, spatial structures and/or rapid temporal or spatial changes of aerodynamic phenomena (transition from laminar to turbulent flow, coherent structures, pitching airfoils in transonic flows with shocks, rotors, test facilities with short run time and different flow temperature etc.) can be investigated. Recently an increasing number of scientists and engineers have started to utilise the PSP technique to investigate pressure distributions from low speed up to hypersonic and cryogenic wind tunnels as well as in turbo machines. The PSP technique has also expanded from the measurement of steady state pressures to include both periodic and unsteady phenomena to study the instantaneous structure of pressure fields in various areas of fluid mechanics. A number of different approaches for paint development, recording and evaluation of PSP images have been described in the literature. This course, which is the third one on PSP organised by DLR Göttingen, Germany, will mainly concentrate on both industrial measurement techniques as well as aspects of the theory of PSP relevant to applications. In addition to lectures on the fundamental aspects of Pressure Sensitive Paint Systems, special emphasis is placed on the presentation of practical and reliable solutions for problems faced during the implementation of the technique in wind tunnels and other test facilities. During practical sessions on the course, participants will have the opportunity to carry out experiments on paint characterisation, coating technique, and the recording and evaluation of PSP data in small groups. Recent developments of the PSP technique such as PSP for unsteady applications and 360° PSP systems for calculation of forces and moments will be discussed and demonstrated