Transonic viscous flow calculations for a turbine cascade with a two equation turbulence model

A numerical method for the study of steady, transonic, turbulent viscous flow through plane turbine cascades is presented. The governing equations are written in Favre-averaged form and closed with a first order model. The turbulent quantities are expressed according to a two-equation kappa-epsilon model where low Reynolds number and compressibility effects are included. The solution is obtained by using a pseudo-unsteady method with improved perturbation propagation properties. The equations are discretized in space by using a finite volume formulation. An explicit multistage dissipative Runge-Kutta algorithm is then used to advance the flow equations in the pseudo-time. First results of calculations compare fairly well with experimental data

Two-dimensional Euler and Navier-Stokes Time accurate simulations of fan rotor flows

Two numerical methods are presented which describe the unsteady flow field in the blade-to-blade plane of an axial fan rotor. These methods solve the compressible, time-dependent, Euler and the compressible, turbulent, time-dependent, Navier-Stokes conservation equations for mass, momentum, and energy. The Navier-Stokes equations are written in Favre-averaged form and are closed with an approximate two-equation turbulence model with low Reynolds number and compressibility effects included. The unsteady aerodynamic component is obtained by superposing inflow or outflow unsteadiness to the steady conditions through time-dependent boundary conditions. The integration in space is performed by using a finite volume scheme, and the integration in time is performed by using k-stage Runge-Kutta schemes, k = 2,5. The numerical integration algorithm allows the reduction of the computational cost of an unsteady simulation involving high frequency disturbances in both CPU time and memory requirements. Less than 200 sec of CPU time are required to advance the Euler equations in a computational grid made up of about 2000 grid during 10,000 time steps on a CRAY Y-MP computer, with a required memory of less than 0.3 megawords

Three-dimensional Euler time accurate simulations of fan rotor-stator interactions

A numerical method useful to describe unsteady 3-D flow fields within turbomachinery stages is presented. The method solves the compressible, time dependent, Euler conservation equations with a finite volume, flux splitting, total variation diminishing, approximately factored, implicit scheme. Multiblock composite gridding is used to partition the flow field into a specified arrangement of blocks with static and dynamic interfaces. The code is optimized to take full advantage of the processing power and speed of the Cray Y/MP supercomputer. The method is applied to the computation of the flow field within a single stage, axial flow fan, thus reproducing the unsteady 3-D rotor-stator interaction

Small Things of Great Importance: Toy Advertising in China, 1910s-1930s

From the turn of the twentieth century, playthings acquired a key role within the Chinese childrearing discourse as tools to train children, the prospective rescuers of China from its perceived decline. As a possibly unintended result, both children and toys acquired a marketing value: advertising employed them as icons to publicize a wide array of products. At the same time, the nascent toy industry "poached" the new discourse to brand its playthings as symbols of (made-in-China) educated progress, seeking to convince the affluent to reject things foreign, and to attract those who wished, through consumption, to participate in an enlightened community. In the reality devised by advertising, playthings would reveal, or construe, parents' affectionate yet progressive competence, whilst children would be shaped into ideal citizens. Drawing on advertisements placed in periodicals for adults and children by Chinese and foreign producers between the 1910s and the 1930s, this study explores the ways in which children and toys were marketed as testimonials and catalysts of cognizant modernity

A new method to warm up lubricating oil to improve the fuel efficiency during cold start

Cold start driving cycles exhibit an increase in friction losses due to the low temperatures of metal and media compared to normal operating engine conditions. These friction losses are responsible for up to 10% penalty in fuel economy over the official drive cycles like the New European Drive Cycle (NEDC), where the temperature of the oil even at the end of the 1180 s of the drive cycle is below the fully warmed up values of between 100°C and 120°C. At engine oil temperatures below 100°C the water from the blow by condensates and dilutes the engine oil in the oil pan which negatively affects engine wear. Therefore engine oil temperatures above 100°C are desirable to minimize engine wear through blow by condensate. The paper presents a new technique to warm up the engine oil that significantly reduces the friction losses and therefore also reduces the fuel economy penalty during a 22°C cold start NEDC. Chassis dynamometer experiments demonstrated fuel economy improvements of over 7% as well as significant emission reductions by rapidly increasing the oil temperature. Oil temperatures were increased by up to 60°C during certain parts of the NEDC. It is shown how a very simple sensitivity analysis can be used to assess the relative size or efficiency of different heat transfer passes and the resulting fuel economy improvement potential of different heat recovery systems system. Due to its simplicity the method is very fast to use and therefore also very cost effective. The method demonstrated a very good correlation for the fuel consumption within ±1% compared to measurements on a vehicle chassis roll

Nanometric Resolution Magnetic Resonance Imaging Methods for Mapping Functional Activity in Neuronal Networks

This contribution highlights and compares some recent achievements in the use of k-space and real space imaging(scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. Atomic size optically detectable spin probe. High magnetic field sensitivity and nanometric resolution. Non-invasive mapping of functional activity in neuronal networks