scholarly journals Vibro-Acoustic Numerical Simulation for Analyzing Floor Noise of a Multi-Unit Residential Structure

2019 ◽  
Vol 9 (20) ◽  
pp. 4289 ◽  
Author(s):  
Sangki Park

In South Korea, the construction of new multi-unit residential structures has been continuously increasing in order to accommodate multiple households in single structures. However, the presence of walls and floors shared with neighbors makes these structures exceptionally vulnerable to floor noise transmission when the noise of everyday life occurs. In particular, South Korea has many social problems associated with such floor noise, which require the utmost attention and immediate resolution. In this study, a 17-story structure was selected as a test structure. Field measurements were carried out. A numerical model for the 17-story structure was developed in order to perform a vibro-acoustic analysis. The validation of the numerical model comparing with the field measurement data results shows a good agreement. Finally, it is concluded that numerical analysis can be applied to resolve floor noise problems arising in multi-unit residential structures.

1998 ◽  
Vol 26 ◽  
pp. 174-178 ◽  
Author(s):  
Peter Gauer

A physically based numerical model of drifting and blowing snow in three-dimensional terrain is developed. The model includes snow transport by saltation and suspension. As an example, a numerical simulation for an Alpine ridge is presented and compared with field measurements.


2006 ◽  
Vol 321-323 ◽  
pp. 451-454
Author(s):  
Joo Young Yoo ◽  
Sung Jin Song ◽  
Chang Hwan Kim ◽  
Hee Jun Jung ◽  
Young Hwan Choi ◽  
...  

In the present study, the synthetic signals from the combo tube are simulated by using commercial electromagnetic numerical analysis software which has been developed based on a volume integral method. A comparison of the simulated signals to the experiments is made for the verification of accuracy, and then evaluation of five deliberated single circumferential indication signals is performed to explore a possibility of using a numerical simulation as a practical calibration tool. The good agreement between the evaluation results for two cases (calibration done by experiments and calibration made by simulation) demonstrates such a high possibility.


2000 ◽  
Vol 31 (1) ◽  
pp. 57-72 ◽  
Author(s):  
N. R. B. Olsen ◽  
D. K. Lysne

A three-dimensional numerical model was used to model water circulation and spatial variation of temperature in Lake Sperillen in Norway. A winter situation was simulated, with thermal stratification and ice cover. The numerical model solved the Navier-Stokes equations on a 3D unstructured non-orthogonal grid with hexahedral cells. The SIMPLE method was used for the pressure coupling and the k-ε model was used to model turbulence, with a modification for density stratification due to the vertical temperature profile. The results were compared with field measurements of the temperature in the lake, indicating the location of the water current. Reasonably good agreement was found.


Author(s):  
Liwu Wang ◽  
Mingzhang Tang ◽  
Sijun Zhang

Abstract In order to study the safe distance between twin-parachute during their inflation process for fighter ejection escape, the fighter was equipped with two canopies and two seats, two types of parachute were used to numerically simulate their inflation process, respectively. One of them is C-9, the other a slot-parachute (S-P). Their physical models were built, then the meshes inside and around both parachutes were generated for fluid-structure interaction (FSI) simulation. The penalty function and the arbitrary Lagrangian-Eulerian (ALE) method were employed in the FSI simulation. To validate the numerical model for FSI simulation, at first the single parachute of the twin-parachute was used for the FSI simulation, the predicted inflation times for both types of parachute were compared with the experimental data. The computed results are in good agreement with experimental data. As a result, the inflation times were predicted with twin-parachute for both kinds of parachute. On the basis of the locations of ejected seats after the separation of seat and pilot, the initial locations and orientations of twin-parachute were also obtained. The numerical simulations for both kinds of parachute were performed by the FSI method, respectively. Our results illustrate that when the interval time for two seats ejected is greater than 0.25s, two pilots attached the twin-parachute are safe, and the twin-parachute would not interfere each other. Moreover, our results also indicate that the FSI simulation for twin-parachute inflation process is feasible for engineering applications and have a great potential for wide use.


2015 ◽  
Vol 29 (18) ◽  
pp. 1550087 ◽  
Author(s):  
Furkan Dincer ◽  
Muharrem Karaaslan ◽  
Emin Unal ◽  
Oguzhan Akgol ◽  
Cumali Sabah

We demonstrate numerically and experimentally chiral metamaterials (MTMs) based on gammadion-bilayer cross-wires that uniaxially create giant optical activity and tunable circular dichroism as a result of the dynamic design. In addition, the suggested structure gives high negative refractive index due to the large chirality in order to obtain an efficient polarization converter. We also present a numerical analysis in order to show the additional features of the proposed chiral MTM in detail. Therefore, a MTM sensor application of the proposed chiral MTM is introduced and discussed. The presented chiral designs offer a much simpler geometry and more efficient outlines. The experimental results are in a good agreement with the numerical simulation. It can be seen from the results that, the suggested chiral MTM can be used as a polarization converter, sensor, etc. for several frequency regimes.


2018 ◽  
Vol 7 (3.29) ◽  
pp. 243
Author(s):  
Sher Afghan Khan ◽  
Mir Owais Ali ◽  
Miah Mohammed Riyadh ◽  
Zahid Hossen ◽  
Nafis Mahdi Arefin

A numerical simulation was carried out to compare various turbulence models simulating axisymmetric nozzle flow past suddenly expanded ducts. The simulations were done for L/D = 10. The convergent-divergent nozzle has been modeled and simulated using the turbulence models: The Standard k-ε model, The Standard k-ω model and The SST k-ω model. Numerical simulations were done for Mach numbers 1.87, 2.2, and 2.58 and the nozzles were operated for NPRs in the range from 3 to 11. From the numerical analysis it is apparent that for a given Mach number and effect of NPR will result in maximum gain or loss of pressure. Numerical results are in good agreement with the experimental results.  


2012 ◽  
Vol 226-228 ◽  
pp. 1488-1494
Author(s):  
Guan Shui Liu ◽  
Lian Wei Sun ◽  
Bo Wang ◽  
Shi Ming Wu ◽  
Cheng Po Hong ◽  
...  

In this work, research was carried out based on the shield tunnel of metro line 1 in Hangzhou. The construction of this tunnel beneath the sewage pipelines, which have large diameter with water pressure. The project studied in this treatise is relatively rare in China in terms of sewer pipes, the number of sewers, spacing between shield and sewers and the crossing times. A numerical model was established to analyze the construction of metro across the sewage pipelines with water pressure, taking the interactions between tunnel, pipelines and soil into account. The stress of pipelines, settlement of pipelines and ground during the crossing process were calculated. The finite element results were compared with measured results to verify the reliability of numerical results. Some meaningful results were achieved.


Author(s):  
Biao Su ◽  
Kaj Riska ◽  
Torgeir Moan

The ice-worthy ship must have a verifiable turning ability in the specified ice conditions. At present, most studies on ship maneuverability in ice are conducted by field measurements. In this paper a numerical method which is introduced for predicting ship performance in level ice, is applied to simulate ship turning in level ice. A real icebreaker is modeled in the simulation program. The calculated results are analyzed and compared with the full-scale data measured during turning tests. A good agreement is achieved.


2011 ◽  
Vol 301-303 ◽  
pp. 352-356 ◽  
Author(s):  
Meng Ling Zhao

The finite element numerical model of 2-D solute transport in ground water with variable was established under the condition of variety of the velocity of the movement of water is not too fast,and was carried on by the finite element numerical simulation method.the numerical simulation shows that the calculated result is in good agreement with the experiment result.


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