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Showing results for tags 'aerodynamics'.
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Hi, I am trying to create a boundary layer mesh around a sphere. It is non uniform boundary layer, what I mean is I am fully aware of how to create a volume mesh with boundary layers. But what I dont know is how I can create a varying number of boundary layers within the domain. Say closer to the sphere, I want 20 layers and near the inlet I need 10 layers. Is there way to create this within Hypermesh? Thanks
Hi, I'm working on my master's thesis and the object of my studies is an aeroacoustic analysis of two automotive mufflers. For validation purposes of acoustics I have the experimental results so it is a benchmark for me. Basically I divided my case into two parts. The first part is to obtain aerodynamics characteristics of mean flow 10m/s inside the muffler , which I'e already done, and the second part is to compute the transmission loss of the muffler using transient CFD simulation and acuFwh post-processor. Before I manage to solve the real case, I decided to calibrate my acusolve environment on a simple expansion chamber muffler and find out if my results will cover with the experimental results. In order to do that I'm working with case from Fig 5, from this research: https://www.acoustics.asn.au/conference_proceedings/AAS2004/ACOUSTIC/PDF/AUTHOR/AC040066.PDF And now I'm really confused because of the boundary conditions and bad resuts I'm getting. As far as I know there are two ways to obtain such results: 1. Single period sinusoid pulse of velocity with ZERO mean flow 2. Single period sinusoid pulse of velocity with NON ZERO mean flow In the paper above, they use the first case, where there is a single period 3200Hz sinusoid pulse with the amplitude of 0.05m/s. But the question is how can I implement it to acusolve? If, let's say, frequencies of interest are of 0-3200Hz as it is above and the sampling frequency is 200kHz than it gives me: T_signal = 1/3200=0,0003125s T_sampl = 1/200000=0.000005s T_signal/T_sampl = 62.5 -> so this is an information for me, that the wave of 3200Hz will be sampled with 62 points using sampling frequency 200kHz, yes? Altair says in their manual that it should be at least 6 points per wavelength in order to properly "create" the wave, so 62>6, and that's OK Now what should I do exactl using acusolve and acuFwh? Should I use Multiplier function at inlet surface of the muffler and create a single period sinusiod of f=3200Hz, but using 5us sampling period as the case above say? Ok, but it is only one period that lasts 0.0003125s so what TOTAL TIME of the simpulation should I use? The thing I know is that I'm "putting" a single pulse without mean flow into the muffler and now I'm "waiting" for response of the system, but the question is how much should I "wait" ? I am really confused so hope to see some help from you. The other question is, if I'm using zero mean flow pulse, then should I turn off any turbulence modeling, because the flow is laminar? PS: I know that CAA is difficult but I have access to a multi CPUs cluster so there is not an issue Regards, Adrian
hello everybody, i have to do an aerodynamic simulation of a race car and i ve done the 2d surface mesh of the shell and of the box (there aren t free edges or t junction). now i ve to do the tetramesh to simulate the fluid domain but it fails all the time and i don t know why.. someone can help me?
Hi all, as per title, which turbulence model that you apply to simulate external aerodynamics case using AcuSolve? and do you change the value of relaxation factor or maintain default setting (=1)? thanks alpharays