Feature Extraction of Oscillating Flow with Vapor Condensation of Moist Air in a Sonic Nozzle

The sonic nozzle is commonly used in flow measurement. However, the non-equilibrium condensation phenomenon of moist air in the nozzle has a negative effect on the measuring accuracy. To investigate this complex phenomenon, the experiments on the oscillating condensation flow of moist air were conducted by an adjustable humidification apparatus with different relative humidity (0-100%), temperature (30-50° C) and carrier gas pressure (1-6 bar), where the micro size pressure measuring system was designed by Bergh-Tijdeman (B-T) Model. The accurate mathematical model of nonequilibrium condensation was also built and validated by the experimental data of time-averaged pressure distribution. Then, the frequency and intensity of pressure fluctuation of oscillating flow at a wide range of operation condition were obtained combining experimental data and physical simulation model. Importantly, a new semi-empirical relation of dimensionless frequency deduced from dimensionless analysis was identified accurately by experimental data. Finally, the signal nonstationarity was also observed by using the continuous wavelet transform (CWT). The instantaneous frequency saltation and the energy attenuation of pressure signals were observed in the condensation flow

An asymptotically compatible probabilistic collocation method for randomly heterogeneous nonlocal problems

In this paper we present an asymptotically compatible meshfree method for solving nonlocal equations with random coefficients, describing diffusion in heterogeneous media. In particular, the random diffusivity coefficient is described by a finite-dimensional random variable or a truncated combination of random variables with the Karhunen-Lo\`{e}ve decomposition, then a probabilistic collocation method (PCM) with sparse grids is employed to sample the stochastic process. On each sample, the deterministic nonlocal diffusion problem is discretized with an optimization-based meshfree quadrature rule. We present rigorous analysis for the proposed scheme and demonstrate convergence for a number of benchmark problems, showing that it sustains the asymptotic compatibility spatially and achieves an algebraic or sub-exponential convergence rate in the random coefficients space as the number of collocation points grows. Finally, to validate the applicability of this approach we consider a randomly heterogeneous nonlocal problem with a given spatial correlation structure, demonstrating that the proposed PCM approach achieves substantial speed-up compared to conventional Monte Carlo simulations

Topology control of VANET based on the multi-radio in vehicle and traffic flow in road network

Za pokretnu mrežu interneta (Vehicular Ad Hoc Networks, VANET), određivanje resursa, pravila industrije transporta i potreba održavanja, rad daje sigurnu i učinkovitu topologiju mobilnog interneta i dizajnira multi-radio čvorove u vozilu, a zatim izrađuje algoritam optimizacije kolonije mrava usmjeren virtualnoj sili kroz topologiju izvornog pristupa kako bi stvorio abstraktnu cestovnu mrežu. Na osnovu tih ideja, gradimo postupak umrežavanja i održavanja u pojedinim dijelovima. Konačno provjeravamo izvedivost i učinkovitost strategije kontrole topologije VANET-a zasnovanu na multi-radiju u vozilu i toku prometa na cestovnoj mreži kroz simulirani eksperiment.For mobile internet network (Vehicular Ad Hoc Networks, VANET), resources allocation, transportation industry regulations and service business requirements, this paper builds a stable and efficient mobile internet topology and designs multi-radio nodes in vehicle, and then raises the virtual-force oriented ant colony optimization algorithm through primal approach topology to abstract road network. Based on these ideas, we design the process of networking and maintenance in sections. Finally, we verify the feasibility and effectiveness of topology control strategy of VANET based on the multi-radio in vehicle and traffic flow in road network through the simulation experiment