Stokes Drift and Meshless Wave Modeling

This dissertation is loosely organized around efforts to improve vertical ocean mixing in global climate models and includes an in-depth analysis of Stokes drift, optimization of a new global climate model wave component, and development of a meshless spectral wave model. Stokes drift (hereafter SD) is an important vector component that appears often in wave-averaged dynamics. Mathematically, SD is the mean difference between Eulerian and Lagrangian velocities and intuitively can be thought of as the near-surface ocean current induced from wave motion. Increasingly, spectral wave models are being used to calculate SD globally. These models solve a 5D wave action balance equation and typically require large computational resources to make short to medium-range forecasts of the sea state. In the first part, a hierarchy of SD approximations are investigated and new approximations that remove systematic biases are derived. A new 1D spectral approximation is used to study the effects of multidirectional waves and directional wave spreading on SD. It is shown that these effects are largely uncorrelated and affect both the magnitude and direction of SD in a nonlinear fashion that is sensitive with depth. In the second part, efforts to add a wave model component to the NCAR Community Earth System Model are discussed. This coupled component will serve as the backbone to a new Langmuir mixing parameterization and uses a modified version of NOAA WAVEWATCH III (a third-generation spectral wave model). In addition, the governing wave action balance equation is reviewed and several variations are derived and formulated. In the third part, construction of a monochromatic spectral wave model using RBF-generated finite differences is described. Several numerical test cases are conducted to measure performance and guide further development. In kinematic comparisons with WAVEWATCH III, the meshless prototype is approximately 70–210 times more accurate and uses a factor of 12 to 17 less unknowns

Calculation of Electric Dipole Oscillator Strength for Polyatomic Molecules Using Floating Spherical Gaussian Orbitals

Physic

On the structural analysis of highway pavements : an application of variational methods

Because of the high financial cost involved in highway construction, it is essential that the most economic methods of design and construction are employed in roadworks. From the design aspect, a road must perform its required function for a specified number of years and the extent to which a pavement fulfils this requirement is largely dependent upon the structural method of design employed. Such a method should be economical, completely reliable, and easily applicable. The main difficulty which arises is that there are a great many parameters involved in any pavement design procedure. These vary from those created by pavement frost effects to those resulting from vehicle wheel configurations. The magnitudes and effects of several of these variables are also difficult to determine quantitatively. In the light of present knowledge it is generally accepted that the ultimate pavement design method will be principally empirical in nature. However, the use of a structural analysis of the pavement as a basis of such an empirical approach is advisable. The analysis should be used to determine the critical stresses, strains and deflections occurring in a pavement and should cover as many as possible of the determinate parameters. This theoretical analysis might then also provide a tool with which the effect of these parameters could be investigated

Sorption Kinetics Part I: A Laboratory Investigation of Six Proposed Rate Laws Using Batch Reactors

Six proposed rate equations for sorption kinetics have been investigated by laboratory batch experiments involving some 270 individual “runs” to determine sorption uptake with time for varying conditions of initial sorbate concentration, temperature, and sorbent species. The sorbate selected was rhodamine-B dye, used because it will sorb readily and is easily measured. Two sorbents, Dowex 50 resin, and Filtrasorb 200 activated carbon were used. Temperature conditions were 10, 20, 30, and 40°C, and concentrations ranged from .0008 to 400 micrograms per ml, rhodamine-B. Analysis of data was computer automated, requiring as input only test conditions, instrument readings, dilutions, and corresponding time. Output of the program for a “set” of data included three different kinds of plots, determination of Langmuir isotherm constants, carious statistical fits, and calculation of rate coefficients for each of the six proposed rate equations along with commensurate plots and statistical analyses. Results indicated that one rate equation in particular showed high R2 correlations with test data. Further analyses established the rate coefficient for this equation in terms of degree of sorbent saturation with sorbate, sorbate concentration in solutions, and temperature of solution