[overture] Re: how to compute velocity and acceleration of a body experiencing irregular motion
- From: Yongsheng Lian <yongshenglian@xxxxxxxxx>
- To: overture@xxxxxxxxxxxxx
- Date: Wed, 13 May 2009 16:41:11 -0400
Hi Bill,
I printed out the variables from MovingGrids.C. Next are the output.
Not sure why the oldT is that defined.
t1=4.0e-2
t2=4.0e-2
t3=4.25e-2
dt=2.5e-3
oldT=cgf3.t=3.5e-2
newT=t3=4.25e-2
deltaT=t3-cgf3.t=7.5e-2
Since the new grid is evaluated so that
g3(t3)<-g1(t1)+(t3-t1)*d(g2(t2/))/dt, I understand that t2 can be
either t1 or t3. But I have no idea why the oldT is three steps back
from the current time.
One more question, in a previous post you fixed a bug in the
MovingGrids.C and RigidBodyMotion.C due to restart. Can you send me
the new .C files? If you can, can you tell me where the bug is since
I have changed quite a lot in both files.
Thanks,
Yongsheng
On Tue, May 12, 2009 at 12:09 AM, Bill Henshaw <henshaw@xxxxxxxx> wrote:
> Hi Yongshen,
>
> How is your motion defined? Is it still a rigid body motion?
> The DeformingBodyMotion class uses the GridEvolution class
> to keep a time history of the moving grids that can be differenced
> in time to get the velocity and acceleration.
>
> Regards,
> Bill
>
> Yongsheng Lian wrote:
>>
>> Hi,
>>
>> Did anyone have similar problem before?
>>
>> Overture uses MovingGrids.C to compute the velocity and acceleration
>> of a moving rigid body. If the motion has a well-defined analytical
>> function, the velocity and acceleration can be computed analytically
>> and efficiently. However, if the motion is not regular, it becomes
>> difficult to evaluate these variables. I recall someone posted before
>> that we can still compute these using the deformingBodyGrids. I need
>> some directions on how to implement it in the code. Any suggestion
>> will be appreciated.
>>
>> Thanks,
>> Yongsheng
>>
>>
>
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