Physical aspects of computing the flow of a viscous fluid

One of the main themes in fluid dynamics at present and in the future is going to be computational fluid dynamics with the primary focus on the determination of drag, flow separation, vortex flows, and unsteady flows. A computation of the flow of a viscous fluid requires an understanding and consideration of the physical aspects of the flow. This is done by identifying the flow regimes and the scales of fluid motion, and the sources of vorticity. Discussions of flow regimes deal with conditions of incompressibility, transitional and turbulent flows, Navier-Stokes and non-Navier-Stokes regimes, shock waves, and strain fields. Discussions of the scales of fluid motion consider transitional and turbulent flows, thin- and slender-shear layers, triple- and four-deck regions, viscous-inviscid interactions, shock waves, strain rates, and temporal scales. In addition, the significance and generation of vorticity are discussed. These physical aspects mainly guide computations of the flow of a viscous fluid

Computational aerodynamics and artificial intelligence

The general principles of artificial intelligence are reviewed and speculations are made concerning how knowledge based systems can accelerate the process of acquiring new knowledge in aerodynamics, how computational fluid dynamics may use expert systems, and how expert systems may speed the design and development process. In addition, the anatomy of an idealized expert system called AERODYNAMICIST is discussed. Resource requirements for using artificial intelligence in computational fluid dynamics and aerodynamics are examined. Three main conclusions are presented. First, there are two related aspects of computational aerodynamics: reasoning and calculating. Second, a substantial portion of reasoning can be achieved with artificial intelligence. It offers the opportunity of using computers as reasoning machines to set the stage for efficient calculating. Third, expert systems are likely to be new assets of institutions involved in aeronautics for various tasks of computational aerodynamics

Flow in a two-dimensional channel with a rectangular cavity

Flow characteristics in two dimensional channel with rectangular cavit

Potential application of artificial concepts to aerodynamic simulation

The concept of artificial intelligence as it applies to computational fluid dynamics simulation is investigated. How expert systems can be adapted to speed the numerical aerodynamic simulation process is also examined. A proposed expert grid generation system is briefly described which, given flow parameters, configuration geometry, and simulation constraints, uses knowledge about the discretization process to determine grid point coordinates, computational surface information, and zonal interface parameters

Relative advantages of thin-layer Navier-Stokes and interactive boundary-layer procedures

Numerical procedures for solving the thin-shear-layer Navier-Stokes equations and for the interaction of solutions to inviscid and boundary-layer equations are described and evaluated. To allow appraisal of the numerical and fluid dynamic abilities of the two schemes, they have been applied to one airfoil as a function of angle of attack at two slightly different Reynolds numbers. The NACA 0012 airfoil has been chosen because it allows comparison with measured lift, drag, and moment and with surface-pressure distributions. Calculations have been performed with algebraic eddy-viscosity formulations, and they include consideration of transition. The results are presented in a form that allows easy appraisal of the accuracy of both procedures and of the relative costs. The interactive procedure is computationally efficient but restrictive relative to the thin-layer Navier-Stokes procedure. The latter procedure does a better job of predicting drag than does the former. In both procedures, the location of transition is crucial for accurate or detailed computations, particularly at high angles of attack. When the upstream influence of pressure field through the shear layer is important, the thin-layer Navier-Stokes procedure has an edge over the interactive procedure

Study of fetomaternal implications in intrauterine growth restriction pregnancies

Background: Fetal growth restriction (FGR) is a pathological condition in which a fetus has not achieved its genetic growth potential. FGR incidence is 6 times higher in underdeveloped and developing countries as compared to the developed world. Methods: This is a retrospective study done in the department of obstetrics and gynaecology, civil hospital and B. J. Medical college, Ahmedabad over the period of 6 months from December 2022 to May 2023. A total of 30 cases of intrauterine growth restriction (IUGR) pregnancies were studied. Results: Majority of the study population, 60% belonged to younger age group of 20-30 years. Multiparity was associated with IUGR babies. Majority of patients i.e. 76.66%. Presented at gestational age of ≥37 weeks and 23.33% at <37 weeks. Most IUGR babies (73.33%) had a birth weight between 2 to 2.5 kg. One third of babies required NICU admission while the perinatal mortality was 10%. Doppler changes in umbilical artery were noted in 27% of cases of IUGR. Among risk factors anemia, preeclampsia and oligohydramnios had equal contributions at 10% each. Previous history for SGA baby is a significant association in 16% of cases. Induction of labor was done in 60% cases, 63% were delivered vaginally and rest via lower segment caesarean section (LSCS), the most common indication of LSCS was fetal distress. Conclusions: The study concluded that IUGR continues to be one of the major etiological factors for fetal morbidity and mortality and increase in rates of LSCS contributing maternal morbidity. IUGR was commonly observed in multigravida patients lacking antenatal care. Anemia and hypertensive disorders of pregnancy as well as oligohydramnios are the potential risk factors for IUGR

Uhlenbeck-Donaldson compactification for framed sheaves on projective surfaces

We construct a compactification $M^{\mu ss}$ of the Uhlenbeck-Donaldson type for the moduli space of slope stable framed bundles. This is a kind of a moduli space of slope semistable framed sheaves. We show that there exists a projective morphism $\gamma \colon M^{ss} \to M^{\mu ss}$, where $M^{ss}$ is the moduli space of S-equivalence classes of Gieseker-semistable framed sheaves. The space $M^{\mu ss}$ has a natural set-theoretic stratification which allows one, via a Hitchin-Kobayashi correspondence, to compare it with the moduli spaces of framed ideal instantons.Comment: 18 pages. v2: a few very minor changes. v3: 27 pages. Several proofs have been considerably expanded, and more explanations have been added. v4: 28 pages. A few minor changes. Final version accepted for publication in Math.

Various analytical models for supercapacitors: a mathematical study

Supercapacitors (SCs) are used extensively in high-power potential energy applications like renewable energy systems, electric vehicles, power electronics, and many other industrial applications. This is due to SCs containing high-power density and the ability to respond spontaneously with fast charging and discharging demands. Advancements in material and fabrication techniques have induced a scope for research to improve the application of SCs. Many researchers have studied various SC properties and their effects on energy storage and management performance. In this paper, various fractional calculus-based SC models are summarized, with emphasis on analytical studies from derived classical SC models. Study prevails such parameterized resistor- capacitor networks have simplified the representation of electrical behavior of SCs to deal with the complicated internal structure. Fractional calculus has been used to develop SC models with the aim of understanding their complicated structure. Finally, the properties of different SC models utilized by various researchers to understand the behavior of SCs are listed using an equivalent circuit

Distance Product of Graphs

In graph theory, different types of product of two graphs have been studied, e.g. Cartesian product, Tensor product, Strong product, etc. Later on, Cartesian product and Tensor product have been generalized by 2-Cartesian product and 2-Tensor product. In this paper, we give one more generalize form, distance product of two graphs. Mainly we discuss the connectedness, bipartiteness and Eulerian property in this product