Equation Solving DRESOR Method for Radiative Transfer in Three-Dimensional Isotropically Scattering Media

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Zhifeng Huang ◽  
Huaichun Zhou ◽  
Guihua Wang ◽  
Pei-feng Hsu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Computation Time ◽  
Discrete Ordinates ◽  
Distinct Advantage ◽  
Reverse Monte Carlo ◽  
Scattering Media ◽  
Equation Solving ◽  
Radiative Intensity ◽  
The Monte Carlo Method

Distributions of ratios of energy scattered or reflected (DRESOR) method is a very efficient tool used to calculate radiative intensity with high directional resolution, which is very useful for inverse analysis. The method is based on the Monte Carlo (MC) method and it can solve radiative problems of great complexity. Unfortunately, it suffers from the drawbacks of the Monte Carlo method, which are large computation time and unavoidable statistical errors. In this work, an equation solving method is applied to calculate DRESOR values instead of using the Monte Carlo sampling in the DRESOR method. The equation solving method obtains very accurate results in much shorter computation time than when using the Monte Carlo method. Radiative intensity with high directional resolution calculated by these two kinds of DRESOR method is compared with that of the reverse Monte Carlo (RMC) method. The equation solving DRESOR (ES-DRESOR) method has better accuracy and much better time efficiency than the Monte Carlo based DRESOR (original DRESOR) method. The ES-DRESOR method shows a distinct advantage for calculating radiative intensity with high directional resolution compared with the reverse Monte Carlo method and the discrete ordinates method (DOM). Heat flux comparisons are also given and the ES-DRESOR method shows very good accuracy.

Reverse Monte Carlo Method for Transient Radiative Transfer in Participating Media

2003 ◽  
Author(s):  
Xiaodong Lu ◽  
Pei-Feng Hsu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Transfer ◽  
Transport Process ◽  
Computational Time ◽  
Reverse Monte Carlo ◽  
Scattering Media ◽  
Participating Media ◽  
Reverse Monte Carlo Method ◽  
Mc Method

The Monte Carlo (MC) method has been widely used to solve radiative transfer problems due to its flexibility and simplicity in simulating the energy transport process in arbitrary geometries with complex boundary conditions. However, the major drawback of the conventional (or forward) Monte Carlo method is the long computational time for converged solution. Reverse or backward Monte Carlo (RMC) is considered as an alternative approach when solutions are only needed at certain locations and time. The reverse algorithm is similar to the conventional method, except that the energy bundle (photons ensemble) is tracked in a time-reversal manner. Its migration is recorded from the detector into the participating medium, rather than from the source to the detector as in the conventional MC. There is no need to keep track of the bundles that do not reach a particular detector. Thus, RMC method takes up much less computation time than the conventional MC method. On the other hand, RMC will generate less information about the transport process as only the information at the specified locations, e.g., detectors, is obtained. In the situation where detailed information of radiative transport across the media is needed the RMC may not be appropriate. RMC algorithm is most suitable for diagnostic applications where inverse analysis is required, e.g., optical imaging and remote sensing. In this study, the development of a reverse Monte Carlo method for transient radiative transfer is presented. The results of non-emitting, absorbing, and anisotropically scattering media subjected to an ultra short light pulse irradiation are compared with the forward Monte Carlo and discrete ordinates methods results.

Monte Carlo Simulation of Radiation in Gases With a Narrow-Band Model and a Net-Exchange Formulation

1996 ◽  
Vol 118 (2) ◽  
pp. 401-407 ◽  
Author(s):  
M. Cherkaoui ◽  
J.-L. Dufresne ◽  
R. Fournier ◽  
J.-Y. Grandpeix ◽  
A. Lahellec
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Computation Time ◽  
Band Model ◽  
One Dimensional ◽  
The Monte Carlo Method ◽  
Reflecting Surfaces ◽  
Heat Transfers ◽  
Narrow Band Model

The Monte Carlo method is used for simulation of radiative heat transfers in nongray gases. The proposed procedure is based on a Net-Exchange Formulation (NEF). Such a formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method: Numerical efficiency becomes independent of optical thickness, strongly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be addressed with very good accuracy. The Exchange Monte Carlo Method (EMCM) is detailed for a one-dimensional slab with diffusely or specularly reflecting surfaces.

Simulation Based Estimation of Extreme Response of Floating Offshore Structures

2007 ◽  
Author(s):  
A. Naess ◽  
O. Gaidai ◽  
P. S. Teigen
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Saddle Point ◽  
Computation Time ◽  
Offshore Structures ◽  
Saddle Point Method ◽  
Response Level ◽  
Random Seas ◽  
The Monte Carlo Method ◽  
Extreme Response

The paper presents a study of the extreme response statistics of a tension leg platform (TLP) subjected to random seas. Two different approaches are compared: A numerical integration method based on saddle point integration and the Monte Carlo method. While the saddle point method is a mathematically attractive technique, which gives numerically very accurate results at low computational costs at any response level, the advantage of the Monte Carlo method is its simplicity and versatility. It is demonstrated in this paper that the commonly assumed obstacle against using the Monte Carlo method for estimating extreme responses, i.e. excessive CPU time, can be circumvented, bringing the computation time down to affordable levels. The agreement between the two approaches is shown to be remarkably good.

UGR CALCULATION BASED ON THE LUMINANCE SPATIAL-ANGULAR DISTRIBUTION

2020 ◽  
Vol 2020 (4) ◽  
pp. 25-32
Author(s):  
Viktor Zheltov ◽  
Viktor Chembaev
Keyword(s):  
Monte Carlo ◽  
Angular Distribution ◽  
Monte Carlo Method ◽  
Visual Task ◽  
New Method ◽  
Lighting System ◽  
Preliminary Assessment ◽  
System A ◽  
The Monte Carlo Method

The article has considered the calculation of the unified glare rating (UGR) based on the luminance spatial-angular distribution (LSAD). The method of local estimations of the Monte Carlo method is proposed as a method for modeling LSAD. On the basis of LSAD, it becomes possible to evaluate the quality of lighting by many criteria, including the generally accepted UGR. UGR allows preliminary assessment of the level of comfort for performing a visual task in a lighting system. A new method of "pixel-by-pixel" calculation of UGR based on LSAD is proposed.

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