Present paper deals with the development of a Mechanistic-Empirical model of the strain-based design of perpetual road pavement using Odemark's principle. The bituminous pavement which can withstand minimum design traffic of 300 msa has been classified as perpetual pavement in this paper. The pavement has been considered as a three-layered system with a top layer of bituminous mix followed by unbound granular materials which rest on soil subgrade. The constituent bituminous layer thickness in the pavement has been determined by limiting the radial tensile strain at the bottom of the bituminous layer against fatigue and the vertical compressive strain at the top of the subgrade against rutting. The allowable strain against rutting and fatigue has been used in the present analysis from mechanistic-empirical correlations recommended in IRC:37-2018. The pavement section has been transformed into a homogeneous system by Odemark's method for application of Boussinesq's theory. To validate the thickness of the perpetual pavement, the strain at different layer interfaces in the pavement was compared using IITPAVE software, which shows the pavement section using present method is safe against rutting but marginally fails under fatigue. Moreover, conventional pavement thickness obtained using IRC:37-2018 were compared with the present method, which shows reasonably good convergence. It has been found that the bituminous layer thickness in a layered system of pavement seems to be more sensitive to fatigue than rutting. In this backdrop, modified fatigue and rutting strain values have been recommended for the design of perpetual road pavement.
For continuous and uninterrupted energy extraction from marine wave motion, most of the existing wave energy extraction systems employ bi-directional turbines. The aerodynamic loss due to the symmetric placement of guide vanes results in a major power output reduction in the system. To optimize this problem, researchers have developed and tested a variety of oscillating water column air turbines. Most commonly used are the axial turbines because of their simplicity and operational ease. The present work focuses on a novel design of an oscillating water column energy extraction system based on a unidirectional axial impulse turbine with a novel rectifying system arrangement which primarily focuses to minimize the losses due to downstream guide vanes and in turn shoot up the power output for low wave height conditions. A numerical model was developed and investigated using RANS equations and k-ω SST turbulence model. The obtained results portray that the proposed flap-based bi-directional impulse system is operationally viable and produces substantially greater power output in comparison to conventional bi-directional and uni-directional turbine systems under low wave height conditions. A hybrid choking scheme was followed which resulted in additional power output. Results show that full choking of the idle turbine is ensured during the inhalation cycle, which was not possible earlier. During the exhalation cycle, additional power output was also obtained from the secondary turbine i.e., front end turbine during exhalation cycle. The proposed system generates maximum total power output at around a flow coefficient of 1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.