CIP Method Research Articles

2604 ソロバン格子CIP法による気液界面の捕獲(OS-26A CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

2604 ソロバン格子CIP法による気液界面の捕獲(OS-26A CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

CIP法によるマルチスケールアナリシス(熱・流体力学・工学におけるマルチスケールモデリング,<特集>理学と工学,科学と技術をつなぐマルチスケールモデリング)

CIP法によるマルチスケールアナリシス(熱・流体力学・工学におけるマルチスケールモデリング,<特集>理学と工学,科学と技術をつなぐマルチスケールモデリング)

2607 CIP法による強非線形船舶・波浪相互作用の3次元数値シミュレーション(OS-26B CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

2607 CIP法による強非線形船舶・波浪相互作用の3次元数値シミュレーション(OS-26B CIP 法および多相流解析技術の最近の進展,OS-26 CIP 法および多相流解析技術の最近の進展)

409 CIP法および差分法を用いた混相燃焼流の数値計算法(J12-1 乱流,反応流,混相流などの解析モデルと数値手法(1),J12 乱流,反応流,混相流などの解析モデルと数値手法,2005年度年次大会)

409 CIP法および差分法を用いた混相燃焼流の数値計算法(J12-1 乱流,反応流,混相流などの解析モデルと数値手法(1),J12 乱流,反応流,混相流などの解析モデルと数値手法,2005年度年次大会)

G132 表面微細構造による熱ふく射波長制御(一般セッション 物性)

To examine influence of microstructure made on an emitter surface, spectrally selective property of the emitter was investigated through numerical simulation and experiment. In the simulation, thermal radiation from solid surface is dealt as hemispherical emission from point sources and Maxwell's equations are solved using CIP method. It was demonstrated that around the wavelength corresponding to the normal mode of cavity resonance, emissivity of the emitter could be amplified, while at wavelengths corresponding to the higher modes, emissivity didn't increase. The results indicated possibility of spectral control by making use of the microstructure on the emitter surface. Furthermore, to verify the validity of simulation results obtained, rectangular microcavities (0.5×0.5×0.5μm^3) were made periodically on nickel emitter surface (2.0×2.0mm^2) through photolithography and fast atom beam etching techniques. Heating of sample was conducted in a vacuum chamber to avoid oxidation and spectral emissivity was measured in the near infrared region. The measured spectral property showed cutoff effect at 1.0μm and amplification of emissive power below that.

ＣＩＰ法における非定常層流圧力損失の高遠高精度計算法

To accurately calculate the transient response in laminar flow, it is necessary to use frequency-dependent friction considering the velocity distribution. We developed a high speed and accurate computing method for simulating the friction in transient laminar pipe flow in the method of characteristics. This method consists of approximating W. Zielke's weighing function as a sum of impulse responses of first order lag systems. This method is normally well-understood. However, it is not usually applied to other calculating methods except the method of characteristics. Because the method of characteristics has a limit to its unique relation between discrete time and space, it is difficult to apply it to complicated pipe systems that include branches. In this paper, we propose application of the high speed and accurate calculating method of frequency-dependent friction to the CIP method. This proposed method has a higher flexibility than the method of characteristics in terms of the relation between discrete time and space. We measured transient response in the single, series, branch and complex pipelines. The results of the numerical calculation agree well with that of the experiment. These results show the effectiveness of the proposed method.

A NEW NUMERICAL SOLVER FOR A2-D NON-LINEAR-SHALLOW WATER EQUATION USING A SOROBAN GRID SYSTEM.

A new numerical scheme to solve a water flow with a free water surface and arbitrary curved ground surface is proposed. In the proposed method, by using a soroban grid system proposed by one of the authors, computational mesh is reconstruct easily at each time step so that some grid points locate on a free water surface exactly. Time development of velocity components and water surface are calculated according to an incompressible inviscid flow equation without any transformation of the equation. Advection effects are calculated by direct interpolation of the CIP method in 3rd order accuracy in spatial. After the advection is solved, acceleration of velocity components due to the pressure gradient is solved using a FDM approach on a soroban grid system. The proposed method is applied to some problems and computational results are examined through comparisons with results of other FDM scheme and theoretical result.

637 非構造格子における4次精度保存スキーム(S04-1 ここまで来たCIP法とその将来(1),S04 ここまで来たCIP法とその将来)

We propose a 4th-order conservative scheme for transport equation on triangular unstructured grids based on the underlying concept of the CIP method. Two types of so-called "moments", defined as the volume integrated average (VIA) and the point value (PV) of physical field are used as the prognostic variables to be carried forward in time separately. VIA is updated by a flux formulation, and PVs are updated by a semi-Lagrangian scheme. A 2D cubic polynomial can be construction over a single triangular element. The 4^<th>-order accuracy of the numerical scheme is verified by numerical tests. The proposed method appears to be very robust to different unstructured grids.

307 CIP法を応用した超高速浮動ブッシュ軸受内側油膜の解析(G.S.機素潤滑設計(軸受・トライボロジー),九州支部 第58期総会・講演会)

307 CIP法を応用した超高速浮動ブッシュ軸受内側油膜の解析(G.S.機素潤滑設計(軸受・トライボロジー),九州支部 第58期総会・講演会)

Three-dimensional numerical simulation of flows with complex geometries in a regular Cartesian grid and its application to blood flow in cerebral artery with multiple aneurysms

We propose a numerical algorithm to compute flows in a complex geometry such as a blood vessel. The algorithm is based on the level set method, the fractional step method, the CIP method and the ghost fluid method in a regular Cartesian grid. The algorithm was applied to various test problems to verify the reliability of method, and numerical results show that the present method can deal with flows in complex geometries such as a bifurcation and multiple aneurysms robustly.

AMR-CIP법을 이용한 이류 방정식에 관한 수치해석

An accurate adaptive mesh refinement based on the CIP method is proposed and It is applied to solve the two dimensional advection equations In tins method, the level set function is employed to refine and merge the computation cells To enhance the accuracy of the solution, the spatial discretization is made by the CIP method The ClP method has many advantages such as the thud order accuracy, less diffusivity, and shape conserving. The mathematical formulation and numerical results are also described. To verify the efficiency, accuracy, and capability of the proposed algoritlun, two dimensional rotating slotted cylinder and Idealized frontogenesis are numerically simulated by the present scheme. As results, It is confirmed that the present method gives an efficient, reasonable solution In the advection equation<br/>

DEVELOPMENT OF DEPTH-AVERAGED INUNDATION FLOW MODEL BASED ON CIP METHOD AND SMAC METHOD

Damage by flood inundation has often occurred in recent years even in urban areas, where water management systems are controlled properly. Advance provision of useful information such as hazard map and evacuation routes to the peripheral people is considered to be necessary in order to prevent and minimize the damage. Development of inundation flow numerical model is, therefore, required to predict flood inundation areas precisely.In the present study, a depth-averaged flood inundation flow model in the Cartesian coordinate system is developed using a CIP method and a SMAC method. The validity of the model was verified by comparing the computed results with existing numerical and experimental ones in the one-dimensional and horizontally two-dimensional fields. As a result, the model was confirmed to be consistent with the existing numerical schemes and be able to reproduce the laboratory experiment with high accuracy.

過熱液中における気泡成長のCIP法による数値解析(熱工学II)

過熱液中における気泡成長のCIP法による数値解析(熱工学II)

CIP法とMPS法の併用による液膜の分裂シミュレーション(G05-8 気泡・粒子・液滴等(2),G05 流体工学部門一般講演)

To predict the motion of a liquid film and its simultaneous breakup within a liquid jet, we have developed a method that combines the CIP method and the MPS method. We simulated the motion of the liquid film using the CIP method and broke it up using the MPS method. Then the surface tensions between the particles for the MPS method on the free surfaces of the liquid jet were calculated using Brackbill's continuum surface force model. The developed method was applied to a cylindrical liquid jet in a uniform air stream. The helical motion of the liquid film caused it to break up. The configurations of the liquid jet were compared to measurements done by Arai and Hashimoto, and the breakup lengths of the liquid jet agreed well with their measurements.

Prediction of Gas Hole by Mold-Filling Simulation with Consideration of Surface Tension

The algorithm for mold-filling simulation with consideration of surface tension has been developed based on the CIP method. As a test problem, a squeeze casting simulation was taken up. As an application to a practical casting problem, we also applied this scheme to a die-casting simulation and compared the numerical results with the experimental data on the size and the position of blow holes. Numerical results both with and without surface tension indicated the existence of blow holes. However, the simulation without surface tension tended to underestimate the size of blow holes. Through these numerical results, it is confirmed that the consideration of surface tension is very important for predicting the size and the position of gas trapped in mold cavities. Furthermore, we propose a criterion for estimating whether the gas remaining in the cavity is compressed or expanded during mold filling, and adopt it to a practical die-casting problem.

A Simple CIP Finite Volume Method for Incompressible Flows

This paper presents a practical numerical method for incompressible flows by combining the concept of the CIP method and the finite volume formulation. The method, namely VSIAM3 (Volume/Surface Integrated Average based Multi-Moment Method), employs two integrated averages, i.e. Volume Integrated Average (VIA) and Surface Integrated Average (SIA) which are generically called integrated moments of the dependent variable herein. Using both VIA and SIA as the model variables, VSIAM3 is different from any existing conventional finite volume method and can be interpreted as the simplest finite volume method of the CIP type. Previous studies show that VSIAM3 has accurate numerical dispersion, compact mesh stencil and flexibility for various fluid problems. In this paper, the author will briefly introduce the general framework of VSIAM3 and its implementation to incompressible flows.

透明パイレックスガラス作製のための焼結温度ならびに雰囲気の影響

Transparent pyrex glasses were obtained by sintering a green compact, which was fabricated by using CIP method for pyrex glass powder, in diverse atmosphere (air, Ar, He and vacuum (10-2Pa)) at 973-1173K. Effects of sintering conditions (temperature and atmosphere) on transmittance of sintered glasses were investigated. Devitrification resulting from crystallization of cristobalite arose in all atmosphere at temperatures over 1023K. Optimum sintering condition for fabricating transparent sintered pyrex glass was at 1003 K for 1hour in a vacuum (10-2 Pa) or He atmosphere in this work. The transparency was 15∼20% in visible region and was about 60% in infrared region. The relationship between transparency and condition of the sintered glasses was discussed in terms of permeation constant of gas species during sintering.

Numerical analysis of nanocluster formation within ns-laser ablation plume

The CIP method is used to calculate macroscopic plume expansion combined with the Zeldovich–Raiser theory for the cluster-formation process such as nucleation and growth. The effect of background gas and latent heat is examined in the one-dimensional case. The latent heats keep the plume temperature at 2500 K for a long period and this explains the delayed photoluminescence. Two contradicting experiments on the size dependence on ambient pressure are clearly explained and are attributed to the difference of laser energy. In two-dimensional simulation, a ‘mushroom-like’ plume shape is replicated, consistent with experimental results.

Numerical method for a moving solid object in flows

We propose a numerical method for dealing with a moving solid body that interacts with a complex liquid surface. The method is based on the level set method, the CIP method, and the ghost fluid method. The validity of the method was shown by applying it to Poiseuille and Couette flow problems. The method can precisely capture the boundary layer as well as a moving solid object.

310 固体と液体の境界をもつ三次元管内流れの CIP 法を用いた研究

310 固体と液体の境界をもつ三次元管内流れの CIP 法を用いた研究