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Old   December 13, 2022, 09:18
Default Validated Three Dimensional Unsteady Finite Element Model, SUITE-3D
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This topic is about 3D unsteady code where source code could be offered:

Validated Three Dimensional Unsteady Finite Element Environmental Model, SUITE-3D, for Advection-Diffusion Flows and Air Pollution

The model herein is about solving the scalar Advection-Diffusion-Source-transport equation for mass. However, it can be used for heat and temperature analyses also. The model could be useful in HVAC studies. Being a finite element code provides the best flexibility in handling complex geometries and boundary conditions. Two and Three-dimensional CFD codes could be also provided for the aerodynamic part and for simulation of air or fluid velocities.

It is required that:
1- The source code and/or the application could be provided to whoever is interested and is offering a good pay. I would like to know also how much does it worth in US $? and your honest estimate is appreciated.
2- Consultation could be also offered in air pollution modelling.
3- Training could also be provided on how to build the model and didactic purposes.
4- Collaborative research for more model developments is possible as I am now working on pollution in street canyons and it would be good to have partner(s) or funding for this project.

Detailed information about the model is in the following journal article while the abstract is enclosed herein for quick look :

Hafez, Y.I. (2022). Validated Three Dimensional Unsteady Finite Element Environmental Model, SUITE-3D, for Advection-Diffusion Flows and Air Pollution. Journal of Engineering Science and Technology Review 15 (3) (2022) 115 -128. DOI: 10.25103/jestr.153.12


Abstract:
A three dimensional unsteady finite element environmental model, SUITE-3D (Solving Unsteady Incompressible Transport Equation in Three Dimensions, 3D), is developed to solve the advection-diffusion transport equation with decay and source terms. Since there is no general analytical solution to the full advection-diffusion transport equation under all possible boundary conditions and under the different equation parameters, an additional model such as SUITE-3D will aid in giving more insights into the phenomenon of advection-diffusion and pollutant transport. It is important to investigate air pollution modelling in the era of climate change and global warming, that our planet earth is facing nowadays. SUITE-3D uses the standard Galerkin’s method without upwinding. Difference schemes are used (central, backward, forward) for the time integration. The finite elements are 8-node cubic brick elements (hexahedrons). Eight Gaussian quadrature points are used for the numerical integration of the element matrices. SUITE-3D is validated against exact solutions of two problems; one has only advection and diffusion terms while the other has advection-diffusion-decay-source terms. The total percentage relative error for the first case was less than 0.61% while it reached 1.0% in the second case. The model is applied to study air pollution dispersion due to a point source pollutant. It is noted that neglecting the x-diffusion term in the Gaussian plume model under calm wind conditions (velocity = 0.2 m/s) results in under-prediction of concentration by 81% at 180 m downstream of the pollutant source. This proves that Gaussian models such as AERMOD provide poor results in situations with low wind speeds, where the three-dimensional diffusion is significant.

Keywords: Three dimensional (3D); Environmental flows, unsteady; advection-diffusion-decay-source; Finite Element Method; Air pollution modeling; Gaussian plume models, AERMOD model

P.S. This code is developed recently after I retired from college and became free lancer and it was not funded by any body at all so I am the sole holder of IP.
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Old   December 21, 2022, 11:12
Default How much does it worth this 3D Unsteady source code for Advection-diffusion-source
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Quote:
Originally Posted by Dr Youssef Hafez View Post
This topic is about 3D unsteady code where source code could be offered:

Validated Three Dimensional Unsteady Finite Element Environmental Model, SUITE-3D, for Advection-Diffusion Flows and Air Pollution

The model herein is about solving the scalar Advection-Diffusion-Source-transport equation for mass. However, it can be used for heat and temperature analyses also. The model could be useful in HVAC studies. Being a finite element code provides the best flexibility in handling complex geometries and boundary conditions. Two and Three-dimensional CFD codes could be also provided for the aerodynamic part and for simulation of air or fluid velocities.

It is required that:
1- The source code and/or the application could be provided to whoever is interested and is offering a good pay. I would like to know also how much does it worth in US $? and your honest estimate is appreciated.
2- Consultation could be also offered in air pollution modelling.
3- Training could also be provided on how to build the model and didactic purposes.
4- Collaborative research for more model developments is possible as I am now working on pollution in street canyons and it would be good to have partner(s) or funding for this project.

Detailed information about the model is in the following journal article while the abstract is enclosed herein for quick look :

Hafez, Y.I. (2022). Validated Three Dimensional Unsteady Finite Element Environmental Model, SUITE-3D, for Advection-Diffusion Flows and Air Pollution. Journal of Engineering Science and Technology Review 15 (3) (2022) 115 -128. DOI: 10.25103/jestr.153.12

Please see attachment for the published manuscript text and tables (because of size limitation on attached files). Graphs will be in another file.


Abstract:
A three dimensional unsteady finite element environmental model, SUITE-3D (Solving Unsteady Incompressible Transport Equation in Three Dimensions, 3D), is developed to solve the advection-diffusion transport equation with decay and source terms. Since there is no general analytical solution to the full advection-diffusion transport equation under all possible boundary conditions and under the different equation parameters, an additional model such as SUITE-3D will aid in giving more insights into the phenomenon of advection-diffusion and pollutant transport. It is important to investigate air pollution modelling in the era of climate change and global warming, that our planet earth is facing nowadays. SUITE-3D uses the standard Galerkin’s method without upwinding. Difference schemes are used (central, backward, forward) for the time integration. The finite elements are 8-node cubic brick elements (hexahedrons). Eight Gaussian quadrature points are used for the numerical integration of the element matrices. SUITE-3D is validated against exact solutions of two problems; one has only advection and diffusion terms while the other has advection-diffusion-decay-source terms. The total percentage relative error for the first case was less than 0.61% while it reached 1.0% in the second case. The model is applied to study air pollution dispersion due to a point source pollutant. It is noted that neglecting the x-diffusion term in the Gaussian plume model under calm wind conditions (velocity = 0.2 m/s) results in under-prediction of concentration by 81% at 180 m downstream of the pollutant source. This proves that Gaussian models such as AERMOD provide poor results in situations with low wind speeds, where the three-dimensional diffusion is significant.

Keywords: Three dimensional (3D); Environmental flows, unsteady; advection-diffusion-decay-source; Finite Element Method; Air pollution modeling; Gaussian plume models, AERMOD model

P.S. This code is developed recently after I retired from college and became free lancer and it was not funded by any body at all so I am the sole holder of IP.
Please tell me How much does it worth this 3D Unsteady source code for solving the Advection-diffusion-source-sink transport differential equation in US $.
Attached Files
File Type: docx Part A Published manuscript text and Tables only.docx (103.3 KB, 2 views)
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Old   December 21, 2022, 16:20
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Am I missing something here? I totally might, but this seems to be a standard scheme for a standard problem. Most cfd /numerical method labs have developed something like this. So either I am missing your unique selling point (I might!), or this code to me has a market value of zero.
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Old   December 22, 2022, 11:20
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Just because similar codes or softwares are available in the market or on the internet it means that we don’t need to see some other different codes with the same functionality. People should not be fond of that every new product must be the best. If it is not the best now it might be that in the future as things evolve. Look long time when Japanese cars first emerged they were not having the quality of today, same about Chinese electric cars now that might later outperform TESLA cars. Diversity must always be there and every product no matter you might think of its importance and value has a value of its own. Would Rolls-Royce be the only car that we should have?? Should Boeing or Airbus be the only aeroplanes that should exist?? Should Pepsi be the only drink?? A code or software that looks to you now as an ordinary or with little value (in your eyes) might evolve in the future into something big.

As mathematical and numerical models and codes are all about predictions, one cannot be sure of their results no matter how many validation tests by any model or code are made. This is because models and codes are tested and validated under certain set of conditions of model parameters and boundary conditions which are often different than the conditions under which the intended problem simulation or prediction is required. This is true no matter you have the best available software in the market (e.g. OPENFOAM , ANSYS, FLOW3D, COMSOL Multiphysics, ABAQUAS, …etc.) as any single software or model still represents one point of view as far as mathematical treatment of the problem at hand.

Therefore, using only one model to investigate a certain phenomenon might not be the best approach as there is no assurance that a single model will produce reliable results. One option to overcome this issue at least partially and not completely is to use a different model or even using several models to tackle the problem at hand. This will allow comparison of the simulation results and if the models’ results are within a narrow and accepted range then the results would have more confidence than when using only one model.

Another reason is that commercial software(s) usually are very general in order to cover as many cases as possible but often the problem at hand would have unique and new features that might not be built yet in the commercial software model and asking the company providing the software for modelling these new features will cost more money and waiting time. There is no guarantee these models’ output would be reliable as these models have very complex structure and any modification even if it is slight requires a lot of work to do. In the meantime, in-house built models usually do not have a complex structure and are relatively easy for almost all modifications.

Take for example the well-known ANSYS CFD code. There are huge number of publications using ANSYS in almost all CFD applications that you might think of (flows in combustion engines, turbines, ducts, pipes, point-source pollution…etc.), so you get the impression that it models everything you can think of; with near exact precision. One can notice that in all the publications about ANSYS they list the equations of motion and the equations for the turbulence model as a closure such as K-e or K-W or else; without explicitly writing the exact expressions for the turbulent stresses. One can assume that it seems that it is a linear turbulent stress-strain rates are used. However, the linear turbulence models are by definition incapable of simulating eddies and secondary motion due to corners or free surfaces or surface roughness irregularities. I am not sure if the current version of ANSYS can predicts the 8 eddies structure for flow in a square duct where secondary motion are due to corner effects. So, to model any flow that include these features (I think almost every flow contains corners, free surface or irregular roughness) a nonlinear turbulent stress-strain rate must be used. Of course due to the nonlinear character it might be extremely difficult to always obtain convergence which is one reason to not including them in commercial software in addition to the mathematical difficulty and complexity of their numerical modelling. The same argument could be presented for free-surface flows and existence of the free surface in turbulent flows generates surface eddy structure. This leaves the floor to in-house built models as they can be case specific with less generality that gives more freedom and flexibility. I think that ANSYS and similar software(s) are not that magical in spite the magical three-dimensional images the vendors or users are presenting.

Another good reason is that commercial software is supplied as application software, i.e., the source code is not provided. This means that it is like a black box where the inside modelling details are hidden. On the other hand, in-house models can provide the source code which make them very transparent and the inside modelling details would be visible.
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Old   December 22, 2022, 22:56
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you are missing the point. There are plenty of open source codes available that can do what your code does. You asked for the market value of your code: zero, because the capabilities are already available for free.
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Old   December 26, 2022, 13:36
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Quote:
Originally Posted by poly_tec View Post
you are missing the point. There are plenty of open source codes available that can do what your code does. You asked for the market value of your code: zero, because the capabilities are already available for free.

The most dangerous thing is to make generic statements based on one’s own experience (especially when it is insufficient and premature experience) without substantiating these statements by any scientific evidences. It is such generic and inaccurate statements that have really zero value.

Any experienced modeller would know that using a different numerical method (e.g. Finite Differences or Finite Volume of Finite Elements) would, generally speaking, produce different results when solving the same differential equation with the same boundary conditions and with the same domain discretization. Not only this but also every particular numerical method has different variations (or sub-method) that results in different predictions. For example, if Mr. ( ) had bothered to read the referenced article about SUITE-3D model, it would have been clear that using the Finite Element Method but with three different interpolation functions have produced totally different results. Table 4 (see attachment here and for more details please see the full article ) shows that even Cheng and Zheng (2020) solving the same problem by two versions of the FEM had different CPU times (they forced having the same accuracy). My code SUITE-3D outperforms Cheng and Zheng (2020) two models as far as either % Relative errors or the CPU time.

So for any valid and scientific opinion about valuing any code it must be based on the same simulation. The differential equation, boundary conditions, initial conditions, domain discretization and time step are stated in the article. So if anyone to compare a code (open or closed source) please run the same case and let us kindly know what you have got.

Of course using higher interpolating polynomial in the Finite Element method would improve the accuracy (while increases the CPU time).
If any comparison is not made based on running the same simulation but made just qualitatively then it has zero value. No code ever has a zero value as every code has its advantages and disadvantages, a fact known by people who really know.

Last edited by Dr Youssef Hafez; December 26, 2022 at 14:58. Reason: Adding attachment
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Old   December 26, 2022, 14:03
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Dude, just stop it.

I did not imply that validating a code is useless. The code & scheme you validated is just obsolete and nothing special. The journal you published the validation paper in is...well...not a Q1 journal.

Implying that I am a greenhorn is quite cute.

You asked for the commercial value of your code. I previously said it was zero because tons of such schemes or similar ones are available for free. I correct that statement: To me, its commercial value is below zero. From your presentation and behaviour here, someone would have to pay me to use it.

The admins may punish me again for this, but if your method for promoting your decade old, obsolete piece of code is to preach at random people on the internet, the validity or commercial value of your code is NOT your problem. You are making a fool of yourself, sir. I am kind enough to tell you that, so if you want to get mad at me for doing that, be my guest.
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Old   December 28, 2022, 13:39
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If there are 1000 CFD codes let them be 1000 and one; what is the problem?
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Old   December 28, 2022, 13:42
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no problem, just commercial value: 0.0
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Old   January 7, 2023, 13:19
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Concerning the say that there are free open source CFD codes available online such as OPENFOAM, it’s developers report that the code has about one-million lines of coding!!!. Honestly, can anyone tell me that he/she has read and fully understood these one-million lines of coding?? This might be possible but to maybe just few very intellectual persons around the word. My code is around several thousands of lines. Just because something is available in the market or the internet it means that we don’t need to see something different of the same kind. Diversity must always be there and every product no matter you might think of its importance and value has a value of its own. Would Rolls-Royce be the only car that we should have?? Should Boeing or Airbus be the only aeroplanes that should exist?? Should PEPSI or COCACOLA be the only drinks to drink?

As mathematical and numerical models and codes are all about predictions, one cannot be sure of their results no matter how many validation tests by any model or code are made. This is because models and codes are tested and validated under certain set of conditions of model parameters and boundary conditions which are often different than the conditions under which the intended problem simulation or prediction is required. This is true no matter you have the best available software in the market (e.g. OPENFOAM , ANSYS, FLOW3D, COMSOL Multiphysics, ABAQUAS, …etc.) as any single software or model still represents one point of view as far as mathematical treatment of the problem at hand.

Therefore, using only one model to investigate a certain phenomenon might not be the best approach as there is no assurance that a single model will produce reliable results. One option to overcome this issue at least partially and not completely is to use a different model or even using several models to tackle the problem at hand. This will allow comparison of the simulation results and if the models’ results are within a narrow and accepted range then the results would have more confidence than when using only one model.


An advantage over commercial software(s) which usually are very general in order to cover as many cases as possible but often the problem at hand would have unique and new features that might not be built yet in the commercial software model and asking the company providing the software for modelling these new features will cost more money and waiting time. There is no guarantee these models’ output would be reliable as these models have very complex structure and any modification even if it is slight requires a lot of work to do. In the meantime, in-house built models usually do not have a complex structure and are relatively easy for almost all modifications. Another good reason is that commercial software is supplied as application software, i.e., the source code is not provided. This means that it is like a black box where the inside modelling details are hidden. On the other hand, in-house models can provide the source code which make them very transparent and the inside modelling details would be visible.
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