Why do particles fly in AOR test?

Fatemeh Hosseini_22198
Fatemeh Hosseini_22198 Altair Community Member
edited February 2023 in Community Q&A

Hello every body,
I did AOR test, but the particles behave weird. Can you guide me why this happen?
Please see the attached video.
(I dont have experimental data of AOR)


Regards,
Fatemeh

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Answers

  • Prasad Avilala_20558
    Prasad Avilala_20558
    Altair Employee
    edited February 2023

    Hi Fatemeh,

    The bulk material behavior is very weird. Is it possible to share the simulation deck to check and understand more about the material behavior?

    The possible reasons for the weird behavior I would expect at this point of time is

    1) Critical time step is lager

    2) Cohesive energy is very high

     

    While sharing the simulation deck, please explain why the material is having high cohesion and what is material behavior you want to study.

     

    Thanks,

    Prasad A

     

  • Fatemeh Hosseini_22198
    Fatemeh Hosseini_22198 Altair Community Member
    edited February 2023

    Many thanks for your response. 

    The timestep has been chosen 20% Rayleigh number. 

    The original particle properties is:
    d= 1micron   E=3.2 E9,     Surface energy=313 mJ/m2. (All these numbers are from literature, I cant measure them)

    I used Cohesion number and reduce E 200 times in order to make the simulation time reasonable . 
    d=1micron   E=1.6 E7     Surface energy= 37.6  mJ/m2.

    (I cant attach .dem file here (it doesnt support).  I will share the table with all properties)

    Regards,
    Fatemeh

  • Prasad Avilala_20558
    Prasad Avilala_20558
    Altair Employee
    edited February 2023
    Fatemeh Hosseini_22198 said:

    Many thanks for your response. 

    The timestep has been chosen 20% Rayleigh number. 

    The original particle properties is:
    d= 1micron   E=3.2 E9,     Surface energy=313 mJ/m2. (All these numbers are from literature, I cant measure them)

    I used Cohesion number and reduce E 200 times in order to make the simulation time reasonable . 
    d=1micron   E=1.6 E7     Surface energy= 37.6  mJ/m2.

    (I cant attach .dem file here (it doesnt support).  I will share the table with all properties)

    Regards,
    Fatemeh

    I Hope contact model chosen is HM+ JKR V2.

    Also, can you please confirm that surface energy  unit is properly taken care meaning in EDEM you should define is J/m2 not mJ/m2.

     

    Thanks,

    Prasad A

  • Fatemeh Hosseini_22198
    Fatemeh Hosseini_22198 Altair Community Member
    edited February 2023
    Prasad Avilala_20558 said:

    I Hope contact model chosen is HM+ JKR V2.

    Also, can you please confirm that surface energy  unit is properly taken care meaning in EDEM you should define is J/m2 not mJ/m2.

     

    Thanks,

    Prasad A

    Thank you Prasad

    I used HM+JKR. Do you believe this could be the issue?
    I believed the differences between the HM-JKR and HM-JKR V2 were minimal.
    (If there is a way to share .dem file with you, please tell me)

    The surface energy is 0.313 J/m2 and 0.037 J/m2 based on EDEM inputs.

    Regards,
    Fatemeh

  • Prasad Avilala_20558
    Prasad Avilala_20558
    Altair Employee
    edited February 2023
    Fatemeh Hosseini_22198 said:

    Thank you Prasad

    I used HM+JKR. Do you believe this could be the issue?
    I believed the differences between the HM-JKR and HM-JKR V2 were minimal.
    (If there is a way to share .dem file with you, please tell me)

    The surface energy is 0.313 J/m2 and 0.037 J/m2 based on EDEM inputs.

    Regards,
    Fatemeh

    You can send it to the mail prasada@altair.com.

    Please share timestep(t)=0;

     

    Thanks,

    Prasad A

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