Hello
Plasma-fluid phenomena are coupled, non-linear, multi-scale in space and time and involve fast ionization, slow recombination and drift-diffusion of a few species of charged particles that also interact with a neutral gas.
Here are some specs to give an idea of the different scales that one must deal with in the case of dielectric barrier discharge actuators.
For time,
due to CFL constraints and Maxwell relaxation times, dt must be less than 10**(-12) but total time of simulation can be hundreds of micro-secs.
(note that ** stands for exponentiation)
whereas spatially,
charge sheaths can be < 10 um near the electrode or at the head of a streamer channel. That channel can be >= 1 cm and the gas dynamics are to be studied over several centimeters.
I am looking for an accurate and stable calculation that will not be too computationally expensive. I will consider first a 2D model.
Can Elmer handle the requirements ?
Have a good night (GMT-6 that is)
Multiphysics covering a wide range in space and time
Re: Multiphysics covering a wide range in space and time
It's OK. I will run the simulation fairly soon and I will keep you posted if the run makes any sense and also if it doe not take too long to execute.
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Re: Multiphysics covering a wide range in space and time
Hi spacedout,
Your question "Can Elmer handle the requirements?" is not easy to answer.
Often with large variarions of scale you can come up with a configuration that is infeasible without some numerical tricks for any code. You probably know your trade well enough to know what things are feasible. Then it more becomes a question of relative cost compared to other software.
Now the space applications don't usually have any "shape" while "body fitted coordinates" is the hall-mark of finite element method. Can you use finite differences with just one mesh parameter and all the benefits of having direct link between coordinate and its (i,j,k) indices? Then generic FEM machinery has hard time competing with FDM.
Compared to other FEM software there should be not so much variation. Elmer has been a MPI code early on and can use a plethora of parallel linear solvers. Many approaches chosen in assembly may have some extra cost associated with the generality. These can be optimized quite a bit following some vectorization and threading strategies used in some more recent modules.
-Peter
Your question "Can Elmer handle the requirements?" is not easy to answer.
Often with large variarions of scale you can come up with a configuration that is infeasible without some numerical tricks for any code. You probably know your trade well enough to know what things are feasible. Then it more becomes a question of relative cost compared to other software.
Now the space applications don't usually have any "shape" while "body fitted coordinates" is the hall-mark of finite element method. Can you use finite differences with just one mesh parameter and all the benefits of having direct link between coordinate and its (i,j,k) indices? Then generic FEM machinery has hard time competing with FDM.
Compared to other FEM software there should be not so much variation. Elmer has been a MPI code early on and can use a plethora of parallel linear solvers. Many approaches chosen in assembly may have some extra cost associated with the generality. These can be optimized quite a bit following some vectorization and threading strategies used in some more recent modules.
-Peter
Re: Multiphysics covering a wide range in space and time
What vacuum cleaner is best for pet hair?
For pet lovers, it’s always nice to have our little friends around us when we’re at home. Their innocence and cuteness can relieve you from stress and fatigue from work. They make you feel loved.
However, as much as we love our pets, there is one thing that all owners are afraid of: pet hair. This is even more accurate for those who have cats or dogs.
If you don’t clean your place frequently, there are high chances that you’ve been breathing in hair-filled air all day long.
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Hence, in this post, we’ll be showing you all the important factors when it comes to picking your new vacuum cleaner.
Suction power
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Maneuverability
In addition, depending on your preferences, the vacuum should come with certain maneuverability, so you can work well with it. To start with, you should care about the weight of your vacuum. Try to go for lightweight vacuum cleaners, instead of heavy ones. The reduced weight and size will make it much easier for you to work in tight spaces.
If you only have a small apartment, and pet hair is your main concern, then handheld vacuums will be a better choice for you, since you can use them for a more concentrated cleaning approach.
Vacuuming head and attachment
Along with the suction power, your vacuum heads play an important role in cleaning up pet hairs. That being said, for this specific type of waste, the flat vacuuming heads with soft bristles are recommended. The unique design works well on most surfaces and floor types, so you’ll find it relatively easy cleaning up your pet hair.
Filtration
You might not know this, but your filter has a close connection to the air quality. That’s because when your vacuum cleaner is operating, it also releases air into the atmospheres. So, if the filtration isn’t working properly, you might breathe in hair-filled air without notice. Hence, it’s recommended that your vacuum cleaner is HEPA filtered.
Bagged vs bagless
Last but not least, we have the ever-raging controversy, and it’s about the use of bagged and bagless vacuum cleaners. Some people believe that using bagged vacuums will help to reduce the amount of dirt being returned to the atmosphere, and some think that using bagless vacuum cleaners is more economic. For us, we think it’s a matter of preference,since not all products are perfect, and the results greatly depend on the owner.
Source: https://www.tweakpc.de/forum/feedback-a ... namen.html
Read more:
Best Rated Vacuum Cleaners
The Best Vacuum Cleaner
Vacuum Cleaner Reviews
What is the best vacuum cleaner - Top rated vacuum cleaner reviews
Best vacuum cleaners in the world - The top rated vacuum cleaners
For pet lovers, it’s always nice to have our little friends around us when we’re at home. Their innocence and cuteness can relieve you from stress and fatigue from work. They make you feel loved.
However, as much as we love our pets, there is one thing that all owners are afraid of: pet hair. This is even more accurate for those who have cats or dogs.
If you don’t clean your place frequently, there are high chances that you’ve been breathing in hair-filled air all day long.
That being said, if this is happening to you, you’ll need to have the room cleaned, and fast. A reliable vacuum cleaner is certainly a great help when it comes to this matter, but first, you’ll need to have yourself the best vacuum cleaner for pet hair.
Hence, in this post, we’ll be showing you all the important factors when it comes to picking your new vacuum cleaner.
Suction power
First things first, regardless of the features and pricing, your vacuum must come with decent suction power, so that it can collect all the scattered hairs in your apartment. If your vacuum has a low suction power, chances are that you won’t collect any dirt and pet hair with it. That being said, your vacuum cleaner should come with a suction power no less than 1000W. Plus, if you have carpet in your house, you might want to invest in a vacuum with even more power.
Maneuverability
In addition, depending on your preferences, the vacuum should come with certain maneuverability, so you can work well with it. To start with, you should care about the weight of your vacuum. Try to go for lightweight vacuum cleaners, instead of heavy ones. The reduced weight and size will make it much easier for you to work in tight spaces.
If you only have a small apartment, and pet hair is your main concern, then handheld vacuums will be a better choice for you, since you can use them for a more concentrated cleaning approach.
Vacuuming head and attachment
Along with the suction power, your vacuum heads play an important role in cleaning up pet hairs. That being said, for this specific type of waste, the flat vacuuming heads with soft bristles are recommended. The unique design works well on most surfaces and floor types, so you’ll find it relatively easy cleaning up your pet hair.
Filtration
You might not know this, but your filter has a close connection to the air quality. That’s because when your vacuum cleaner is operating, it also releases air into the atmospheres. So, if the filtration isn’t working properly, you might breathe in hair-filled air without notice. Hence, it’s recommended that your vacuum cleaner is HEPA filtered.
Bagged vs bagless
Last but not least, we have the ever-raging controversy, and it’s about the use of bagged and bagless vacuum cleaners. Some people believe that using bagged vacuums will help to reduce the amount of dirt being returned to the atmosphere, and some think that using bagless vacuum cleaners is more economic. For us, we think it’s a matter of preference,since not all products are perfect, and the results greatly depend on the owner.
Source: https://www.tweakpc.de/forum/feedback-a ... namen.html
Read more:
Best Rated Vacuum Cleaners The Best Vacuum Cleaner Vacuum Cleaner Reviews What is the best vacuum cleaner - Top rated vacuum cleaner reviews Best vacuum cleaners in the world - The top rated vacuum cleaners