Sensitivity tests, velocity models

Fthenakis, Schatz, and Zakkay 1991 Develop computer simulationss of the Hawk, Nevada Test Site, field tests of water sprays to absorb HF releases. Computer model HFSPRAY developed amd validated against all the Hawk field data. Accurate specification of nozzle parameters is essential sensitivity analysis with model indicated that not only drop size variations but also variation of initial drop velocity and spray pattern can have a measurable effect on model predictions. 

Figure 15 Model results for sensitivity tests of the " He flux value for the Carrizo aquifer—(a-e) caleulated ( He)exc curves for five different orders of magnitude of the flux value, between 3.6 X 10 cm STP cm yr and 3.6 X 10 em STP cm yr and a eonstant velocity value of 1.61 m yr The calculated concentration curves for the bottom (z = 230 m) and for the top (z = 0 m) of the aquifer are represented. The measured (" He)exc concentration values in the aquifer are also shown (Castro et aL, 2000) (reproduced by permission of Elsevier from Appl. Geochem.

Fig. 3. (a) Sensitivity test of the higher-mode waveforms to the depth to the base of the upper-mantle lid for the SLR seismogram of the 18 July 1986 earthquake (Fig. 1, event 2). The continuous line is the observed waveform, the dotted line is the synthetic for the southern Africa velocity model of Qiu et al. (1996), and the dashed line is the synthetic for the same velocity model but with the lid base increased to the depth indicated at the left of each seismogram, (b) Same as (a) but for the SLR seismogram of the 10 March 1989 earthquake (Fig. 1, event 5). (c) Same as (a) but for the SUR seismogram of the 24 July 1991 earthquake to the minimum S-wave velocity of the low-velocity zone (LVZ). 

Figure 9.7 Sensitivity tests to urban features with the DMI-HIRLAM high resolution model shown as the difference fields (runs without vs. with modifications) for the 2-m temperature (upper row) and 10-m wind velocity (lower row) separately with the inclusion of the AHF (left) and urban roughness (right) over the Copenhagen and Malmo metropolitan areas on 30 March 2005.

Testing the sensitivity of a model for correct simulation of ocean model velocity fields. 

To test this model by determining the sensitivity of the front velocity to the concentrations of ferroin, [BrOJ]o, and [H ]o. 

Although they are increasingly popular, computational fluid dynamic (CFD) calculations are notoriously difficult to validate Model equations may be available to the user, but the source code is typically proprietary, experimental data for comparison may be impossible to obtain, and the sheer volume of data available from the simulations makes complete and meaningful validations extremely difficult. Velocity measurements are difficult. Pressure drop measurements are easy but insensitive to the details of the flow. The RTD is a more sensitive test, but it is not unique since the RTD is derived from a flow-averaged velocity profile... 

Many factors influence the accuracy of experimental data and each experimental run could be described by a different set of parameters n, K, Ty. Since the flow models strongly depend on input data and their evaluation, a sensitivity analysis was used to find effect of value of flow behaviour index n on accuracy of laminar and turbulent flow models. Dependency of slurry/water pressure gradient ratio i / io on mean slurry velocity V of the measured slurries for both tested turbulent models and yield power-law model is shown in Fig. 4, where also a role of parameter n is illustrated. The value of n given by best fitting of laminar data by Eq. (4) represents quite well laminar region. For turbulent data it is not valid (see dashed line). The best fitting value n for turbulent data varies not only with kind of solid material, but depends also on concentration. 

These tests demonstrate the sensitivity of the higher-mode data to the upper-mantle structure. Figure 4a shows the displacement amplitude v. depth for the fundamental and first eight higher Rayleigh modes at 15 s period for the southern African model shown at the left in the figure. The fundamental mode at this period is sensitive to the velocity structure in the top c. 50 km of the model, whereas the higher modes are... 

The power law exponent, n, is unity for a Newtonian fluid and less than unity for a shear-thinning fluid. One of the central questions of polymer physics concerns the molecular basis for the constitutive equations. Because NMR is so sensitive to molecular dynamical parameters, the simultaneous mapping of velocity profiles and molecular properties such as the polymer self-diffusion coefficient by means of the dynamic NMR microscopy technique offers an effective test of much molecular models. 

---