Complex geometry, measures

One obvious disadvantage with both the approaches mentioned above is that the attenuation measurements are based on through-transmission, TT, testing which means that we need access to both sides of the specimen and this cannot be guaranteed for many of the complex geometries found, e.g., in the aircraft industry. 

Ventilation components with small geometric detail Numerical modeling of diffusers with complex geometry is difficult. Therefore, it is more reliable to measure airflow around such devices at full scale. 

In summary, we have commented briefly on the microscopic applications of NMR velocity imaging in complex polymer flows in complex geometries, where these applications have been termed Rheo-NMR [23]. As some of these complex geometries can be easily established in small scales, NMR velocimetry and visc-ometry at microscopic resolution can provide an effective means to image the entire Eulerian velocity field experimentally and to measure extensional properties in elastic liquids non-invasively. 

Viscometers of relatively complex geometry, for example the Ostwald glass U-tube viscometer, can be used to measure the viscosity of Newtonian liquids, which is independent of shear rate and time, after calibration with a Newtonian liquid of known viscosity. Such instruments cannot be used for Theologically characterizing non-Newtonian liquids, and therefore cannot be classed as rheometers, as geometrical complexity prevents evaluation of shear stress and shear rate at a given location independently of sample rheological behavior. 

A quantitative comparison between the numerical model and experimental data can be made using those measurements of bubble volume and bubble rise velocity. The calculated values of bubble volume and bubble rise velocity for both ambient and high pressure conditions and also for some complex geometries such as the Westinghouse Cold Flow 30 cm diameter semi-circular model, are shown as large symbols in Figure 2. The specific geometries and flow conditions for the calculations are listed in Table I. 

The throwing power of a bath is a measure of its ability to produce electroplated coatings of uniform thickness on samples having complex geometries. A quantitative measure of this property can be defined in terms of the so-called Haring and Blum cell, which is used to determine it. In this cell, two cathodes are positioned at unequal distances from two sides of an anode, as shown in Fig. 24M. The throwing power (T.P.) is defined as ... 

Many different designs of surrogate surfaces have been used to measure dry deposition in the field. These include smooth flat surfaces, rough flat surfaces, and collectors with complex geometries. Examples of additional design modifications include application of an adhesive coating to minimize particle resuspension, covering the surface with a film of water to study... 

In a complex geometry, such as the present Triple Annular Research Swirler (TARS) in which several co-swirling or counter-swirling flows interact, the vortical evolution and breakdown are complex. Detailed velocity measurements are necessary to resolve the physical processes that involve mixing and interaction of three distinct air streams [4], As the first phase of this project, nonreacting velocity flow fields downstream of TARS were studied by LDV and PIV. Basic flow structures are discerned by the experimental data, and comparison of flow structure caused by different swirler combinations is made. 

Computer modeling of convection has had mixed success. Many convection problems, particularly those involving laminar flow, can readily be solved by special computer programs. However, in situations where turbulence and complex geometries are involved, computer analysis and modeling are still under development. Mass transfer analogies can play a key role in the study of convective heat transfer processes. Two mass transfer systems, the sublimation technique and the electrochemical technique, are of particular interest because of their convenience and advantages relative to direct heat transfer measurements. 

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