Valuation of Mortgage Backed Securities Using Finite Differential Method and Parallel Computation

2021 ◽  
Vol 46 (3) ◽  
pp. 9-34
Author(s):  
Yongsik Kim ◽  
Jeongbok Son ◽  
Jane Yoo
Keyword(s):  
Parallel Computation ◽  
Differential Method ◽  
Mortgage Backed Securities ◽  
Finite Differential Method

Thermohydrodynamic Lubrication Analysis of Slider Bearings With Steps on Bearing Surface

2009 ◽  
Author(s):  
Hideki Ogata
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Fluid Velocity ◽  
Differential Method ◽  
Fluid Film ◽  
Bearing Surface ◽  
Fluid Film Bearings ◽  
Temperature Distributions ◽  
Finite Differential Method ◽  
Good Agreement

This study focuses on the thermohydrodynamic lubrication analysis of fluid film bearings with step on the surface such as a Rayleigh step bearing. In general, the Reynolds equation does not satisfy the continuity of the fluid velocity components at steps. This discontinuity results in the difficulty to solve the energy equation for the lubricants, because the energy equation needs the velocity components explicitly. The author has solved this problem by introducing the equivalent clearance height and the equivalent gradient of clearance height at steps. These parameters remove the discontinuity of velocity components and the energy equation as well, so that one can solve these equations on all of the bearing surfaces including the step region by finite differential method (FDM). The numerical results of pressure and temperature distributions by the proposed method for a Rayleigh step bearing were compared with the results obtained by a commercial CFD package. These results showed good agreement with each other. This method is extended to 2D unequal grid problems.

An Electrothermal Model for IGBT Based on Finite Differential Method

2020 ◽  
Vol 8 (1) ◽  
pp. 673-684 ◽  
Author(s):  
Han Cao ◽  
Puqi Ning ◽  
Xuhui Wen ◽  
Tianshu Yuan ◽  
Huakang Li
Keyword(s):  
Differential Method ◽  
Finite Differential Method

scholarly journals Analysis of Operability Envelopes for Subsea Production Tree Installation

2019 ◽  
Author(s):  
Fei Wang ◽  
Neng Chen
Keyword(s):  
Mathematical Model ◽  
Drill Pipe ◽  
Differential Method ◽  
Ocean Current ◽  
Mechanical Behaviors ◽  
Governing Equations ◽  
Operation Conditions ◽  
Current Water ◽  
Ocean Conditions ◽  
Finite Differential Method

The article presents a mathematical model to investigate the operability envelopes for subsea production tress (SPT) installation using drill pipe. The finite differential method was used to solve the established governing equations in which the ocean conditions were considered. Based on the evaluations of the ocean wave, ocean current, water depth, specification of drill pipe and SPT weight that might dominate the mechanical behaviors of the pipe, the operability envelopes with permissible ocean conditions for SPT installation were obtained. The results indicate that changes of depths in deep water and SPT weight have few effects on the operation conditions and it would be better to choose smaller pipe to obtain larger permissible ocean conditions during SPT installation.

scholarly journals Numerical Evaluation of Rotordynamic Coefficients for Compliant Foil Gas Seal

2020 ◽  
Vol 10 (11) ◽  
pp. 3828 ◽  
Author(s):  
Xueliang Wang ◽  
Meihong Liu ◽  
Sharon Kao-Walter ◽  
Xiangping Hu
Keyword(s):  
Flow Field ◽  
Numerical Evaluation ◽  
Flow System ◽  
Differential Method ◽  
Operating Parameters ◽  
Test Rig ◽  
Operation Performance ◽  
Rotordynamic Coefficients ◽  
Aero Engine ◽  
Finite Differential Method

Compliant foil gas seal is one of the advanced cylindrical gas seal technologies and can be commonly used in the secondary flow system of an aero-engine. It can enhance the dynamic stability of the aero-engine by meeting the steady requirements of the aero-engine seal system. To evaluate the performance of compliant foil gas seal, the steady performance of the gas seal is firstly analyzed to predict the sealing efficiency and obtain the pressure distribution of the gas seal in the compressible flow field. Then, the effects of the operating parameters on the rotordynamic coefficients are analyzed using the finite differential method. It can be used to predict the operation performance of the aero-engine and prepare for the optimization and test rig of compliant foil gas seal on the T-shaped groove.

Numerical Analysis on Hybrid High Speed Sleeve Bearing

2006 ◽  
Vol 315-316 ◽  
pp. 531-535
Author(s):  
L.L. Wang ◽  
Pei Qi Ge ◽  
Chang Hou Lu
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Principal Axis ◽  
Differential Method ◽  
Lubricating Oil ◽  
Loading Capacity ◽  
Sleeve Bearing ◽  
Principal Axis System ◽  
Spiral Angle ◽  
Finite Differential Method

Hybrid sleeve bearing is widely used in high speed principal axis system. Numerical analysis on a spiral oil wedges hybrid sleeve bearing of high speed principal axis is investigated in this paper. The finite differential equations of Reynolds, film thickness and velocity in an oblique coordinate system are obtained. By means of the finite differential method, loading capacity, pressure distribution, and stream of lubricating oil of the hybrid sleeve bearing are computed and analyzed. The results show that spiral oil wedges can produce the flow separation between hot oil and cold oil, and avoid the oil heated repeatedly. With the increase of eccentricity and decrease of spiral angle, the loading capacity of the bearing increases.

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