MindMap Gallery comsol basics
This is a mind map about the basics of comsol. The main content includes: preparation before starting the simulation task, and the basics of multi-physics calculations. The introduction is detailed and the description is comprehensive. I hope it will be helpful to those who are interested!
Edited at 2024-11-19 20:22:24魯米:靈性覺醒的10個維度。當你停止尋找自己,便會找到整個宇宙,因為你正在尋找的東西,也在尋找你。任何你每天持之以恆在做的事情,都可以為你打開一扇通向精神深處的門。靜默中,我滑入祕境,萬般皆妙樂觀察身邊的神奇,不要聲張。你生而有翼,為何喜歡爬行?靈魂擁有了它自己的耳朵,能夠聽到頭腦無法理解的事情。向內尋求一切的答案吧,宇宙中的一切都在你體內。情人們並不最終相遇某處,這個世界沒有離別。傷口是光進入你內心的地方。
慢性心力衰竭,不僅僅是心率的快慢問題!它源於心肌收縮與舒張功能的下降,導致心輸出量不足,進而引發肺循環充血和體循環淤血。從病因、誘因到代償機制,心衰的病理生理過程複雜多樣。通過控制水腫、減輕心臟前後負荷、改善心臟舒縮功能,以及防治基本病因,我們可以有效應對這一挑戰。了解心衰的機制與臨床表現,掌握防治策略,才能更好地守護心臟健康。
缺血再灌注損傷是器官或組織恢復血液供應後,細胞功能代謝障礙和結構破壞反而加重的現象。其主要機制包括自由基生成增多、鈣超載以及微血管和白細胞的作用。心臟和腦是常見的受損器官,表現為心肌代謝和超微結構變化、心功能下降等。防治措施包括清除自由基、減輕鈣超載、改善代謝和控制再灌注條件,如低鈉、低溫、低壓等。理解這些機制有助於製定有效治療方案,減輕缺血性損傷。
魯米:靈性覺醒的10個維度。當你停止尋找自己,便會找到整個宇宙,因為你正在尋找的東西,也在尋找你。任何你每天持之以恆在做的事情,都可以為你打開一扇通向精神深處的門。靜默中,我滑入祕境,萬般皆妙樂觀察身邊的神奇,不要聲張。你生而有翼,為何喜歡爬行?靈魂擁有了它自己的耳朵,能夠聽到頭腦無法理解的事情。向內尋求一切的答案吧,宇宙中的一切都在你體內。情人們並不最終相遇某處,這個世界沒有離別。傷口是光進入你內心的地方。
慢性心力衰竭,不僅僅是心率的快慢問題!它源於心肌收縮與舒張功能的下降,導致心輸出量不足,進而引發肺循環充血和體循環淤血。從病因、誘因到代償機制,心衰的病理生理過程複雜多樣。通過控制水腫、減輕心臟前後負荷、改善心臟舒縮功能,以及防治基本病因,我們可以有效應對這一挑戰。了解心衰的機制與臨床表現,掌握防治策略,才能更好地守護心臟健康。
缺血再灌注損傷是器官或組織恢復血液供應後,細胞功能代謝障礙和結構破壞反而加重的現象。其主要機制包括自由基生成增多、鈣超載以及微血管和白細胞的作用。心臟和腦是常見的受損器官,表現為心肌代謝和超微結構變化、心功能下降等。防治措施包括清除自由基、減輕鈣超載、改善代謝和控制再灌注條件,如低鈉、低溫、低壓等。理解這些機制有助於製定有效治療方案,減輕缺血性損傷。
central theme
Preparations before starting the simulation task
DIPOA
definition
Determine the research object, research questions, physical quantities, and applicable physical equations
enter
Physical parameters needed to solve the equation
Changes in physical parameters
boundary conditions
initial conditions
size and units
process
Choose appropriate calculation programs and software based on physical equations, assumptions, physical spatial scale, etc.
COMSOL: using finite element method, multi-field coupling, suitable for macro scale
fluent: finite volume method
MS, Dalton: Molecular dynamics software, suitable for atomic scale
output
Express equation solution results
Source data in tabular form
Graph
2D color picture
three dimensional view
animation
analyze
Reasonable analysis of data results
A summary of the good verification of previous work
Reasonably explain and optimize existing problems
can be further studied in the future
Multiphysics calculation basics
finite element method
Basic idea
Approximate the irregular solution domain into many regular-shaped continuous subdomains. The subdomains are called grid cells. The vertices of the cells are the exact solutions of the equations (groups). The interior of the grid is approximated by interpolation.
Basic steps
Regional discreteness and division
Choice of interpolation function
Creation of a system of equations
Solving systems of equations
Mathematical theoretical basis
Continuously differentiable
Requires the function to be continuously differentiable
Otherwise, an error is reported: the calculation does not converge or the initial value fails to be solved.
Manually using the Step function: smoothing function
Differentiable
A function of one variable must be differentiable if it is differentiable
Multivariate functions are differentiable but not necessarily differentiable. Partial derivatives are required to exist and be continuous.
Are derivatives and differentials generally equivalent in COMSOL? Used to express the rate of change of a physical quantity over time or space
gradient
Used to express the speed of change of physical quantities
Use contour observations in results
For areas with large gradients, local grid subdivision is required to ensure calculation accuracy.
flux
Used to represent the transport intensity of a certain attribute quantity
divergence
The degree of divergence of the vector field at each point in space
Positive source (divergent source)
Negative source (hole, sink)
Passive
curl
Less commonly used in COMSOL
numerical analysis
error
relative error
absolute error
Need to be considered during geometric modeling and numerical solution
Generally, the system default relative tolerance is 10^(-6)
numerical stability
The algorithm is insensitive to errors in the calculation process
During the calculation process, the relative tolerance error gradually decreases until it is less than the relative tolerance.
Convergence plots can be observed to detect
How to observe the convergence plot?
pathological problem
When the input data has small fluctuations, it will cause very large disturbances in the results.
Cause
mathematical model itself
boundary conditions
Solver settings
Core terms of basic physics fields
Governing equations
Definite solution conditions
boundary conditions
initial value
Common physical quantities
stress
The force generated by the structure’s resistance to load = load/section area (Pa)
Indicators to determine whether products and structures are susceptible to damage
strain
The ratio of the deformation amount of a certain point to its undeformed length (dimensionless)
Used to determine whether the structure is damaged, that is, whether its stress has reached the strength limit
Also used to evaluate stiffness
anisotropy
isotropic
electric field
magnetic field
concentration
mass concentration
molarity
subtopic