Study on Coupling Model of Physical and Numerical Models in Estuarine Area

Author(s):  
Xiaofeng Luo ◽  
Chuanteng Lu ◽  
Zhichang Chen
2017 ◽  
Vol 23 (6) ◽  
pp. 1130-1135
Author(s):  
Kun Wang ◽  
Juntong Xi

Purpose This paper aims to present a method based on dynamics to find the transient pressure at the nozzle area of a piezoelectric inkjet printer. This pressure responds to input signals of the piezoelectric driver deformation. The pressure at the nozzle is the boundary condition of the computational fluid dynamics model of the inkjet printer nozzle, and serves as the “bridge” between the piezoelectric driver actuation and the droplet generation of an inkjet printer. Design/methodology/approach The transient pressure was estimated using a fluid-solid coupling numerical model of the printerhead. In this study, a simple step-shape signal was applied. The printerhead chamber was considered to act as a linear Helmholtz resonator to determine the system transfer function between the input of driver deformation and the output of pressure. By decomposing the input signal into several simple signals, the transient pressure is the superposition of those calculated pressures. Findings The pressure values determined by transfer function and by superposition match the pressure values directly calculated by a fluid-solid coupling model. This demonstrates the rationality and practicability of the method. Originality/value This paper proposes a method to identify a proper boundary condition of pressure for numerical models that only include the fluid field around the nozzle. This strategy eliminates the need to calculate the complex and unstable fluid-solid coupling for every pattern of input. Additionally, the suitable boundary condition of transient pressure can be set rather than relying on the shape of the PZT driver deformation signal.


2012 ◽  
Vol 629 ◽  
pp. 581-586
Author(s):  
Zhi Jiang Yuan ◽  
Lian Gan Jin ◽  
Wei Chi ◽  
Heng Dou Tian

Underwater towed systems have the many applications in exploitation of underwater environments. While in the research exists which is about the numerical models of towed system, the relatively simple model of the towed body is used and the dynamic of the towing ship is neglected. The towing ship as part of towed system, its heave and pitch motion are coupled and highly non-linear. Considering the dynamic of three parts of towed system is important. In the paper, a newly couple model is developed to predict the behaviors of underwater towed systems under effect of the heave and pitch motion of towing ship. We use a finite difference method as the towed cable and is coupled with the non-linear numerical models of a towing ship and a towed body. Illustrative application of the coupling model is presented. The numerical results show the heave and pitch motion of towing ship affect the motion of towed body.


2020 ◽  
Vol 82 ◽  
pp. 149-160
Author(s):  
N Kargapolova

Numerical models of the heat index time series and spatio-temporal fields can be used for a variety of purposes, from the study of the dynamics of heat waves to projections of the influence of future climate on humans. To conduct these studies one must have efficient numerical models that successfully reproduce key features of the real weather processes. In this study, 2 numerical stochastic models of the spatio-temporal non-Gaussian field of the average daily heat index (ADHI) are considered. The field is simulated on an irregular grid determined by the location of weather stations. The first model is based on the method of the inverse distribution function. The second model is constructed using the normalization method. Real data collected at weather stations located in southern Russia are used to both determine the input parameters and to verify the proposed models. It is shown that the first model reproduces the properties of the real field of the ADHI more precisely compared to the second one, but the numerical implementation of the first model is significantly more time consuming. In the future, it is intended to transform the models presented to a numerical model of the conditional spatio-temporal field of the ADHI defined on a dense spatio-temporal grid and to use the model constructed for the stochastic forecasting of the heat index.


2003 ◽  
Vol 59 (3-4) ◽  
pp. 10
Author(s):  
D. Yu. Kulik ◽  
S. L. Senkevich ◽  
Victor Ivanovich Tkachenko
Keyword(s):  

2019 ◽  
Vol 2019 (4) ◽  
pp. 23-31
Author(s):  
Jakub Wilk ◽  
Radosław Guzikowski

Abstract The paper presents the validation procedure of the model used in the analysis of the composite blade for the rotor of the ILX-27 rotorcraft, designed and manufactured in the Institute of Aviation, by means of numerical analyses and tests of composite elements. Numerical analysis using finite element method and experimental studies of three research objects made of basic materials comprising the blade structure – carbon-epoxy laminate, glass-epoxy composite made of roving and foam filler – were carried out. The elements were in the form of four-point bent beams, and for comparison of the results the deflection arrow values in the middle of the beam and axial deformations on the upper and lower surfaces were selected. The procedure allowed to adjust the discrete model to real objects and to verify and correct the material data used in the strength analysis of the designed blade.


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