The Shock - Elliptical Bubble Interaction

The contents of this page were presented at the joint APS/AAPT conference in Washington D.C., April 1997. Download viewgraphs here. (Postscript, tarred & gzipped. 0.97 Mb)


Old hat;
Run 4 Picture Animation (540K) 		Shock - bubble interactions have been much examined and studied. The interaction fragments the bubble which then proceed to move away from the site of the interaction. To date most studies have concentrated on symmetric interactions. Here is what a symmetric interaction of a shock with an elliptical bubble looks like. (280K) The parameters are that of Run 4 . Euler simulation, Godunov method, done on the CM5, NCSA; 128 procs crunching for 180 mins (CPU time). t=1.0 corresponds to half bubble-crushing time. As an aside, this is what an edge detection algorithm run on the previous picture looks like.

Detailed density plots for the interaction: frames 1, 2, 3, 4 and 5
Detailed vorticity plots for the interaction: frames 1, 2, 3, 4 and 5

Premise;
Run 5;
Pic1
Pic2 Animation 		We surmise that breaking the symmetry will result in enhanced mixing or transportation of fragments away from the initial site. We tilt the previous ellipse by 60 degrees from the vertical; the pictures show the effect. The parameters correspond to Run 5 .
  1. Picture 1 (211K)
  2. Picture 2 (300K)
  3. Animation (570K)
AR=3.0;
Run 7;
Pic1,
Pic2. Animation 		To investigate the effect of the Aspect Ratio of the ellipse, we made another run. The fragmentation and redistribution of mass follows a very different pattern as shown in the pictures below. The parameters correspond to Run 7 .
  1. Picture 1 (158K)
  2. Picture 2 (220K)
  3. Animation (525K)
M=10.0;
Run 8 & Run 10;
Pic1,
Pic2. Animation 		We make a canonical M=10, eta=10.0 run to investigate the effect of the Mach number. The aspect ratio is 1.5, the resolution is 1000 X 160, quarter the resolution of the previous run. The solver is an EFM solver. The redistribution of mass follows a different pattern than the runs before; we are trying to ascertain if the lower resolution or the EFM solver is responsible. Computer time: 15hrs on an 8 proc SP2, running dedicated. The parameters are in Run 8 & Run 10.

  1. Picture 1(a) [coarse res] (129K)
  2. Picture 1(b) [normal res; dx=dy=0.5e-3] (121K) [Run 10]
  3. Picture 2 [coarse res] (190K)
  4. Picture 2(b) [normal res; dx=dy=0.5e-3] (200K) [Run 10]
  5. Animation (630K)

The high resolution run seems to show a few differences; here is an interfacial circulation plot and here a comparison of postive and negative vorticity . Also, here is a comparison between interfacial and domain circulations.

M=10.0;
Run 9;
Pic1,
Pic2.
Animation 		We make a canonical M=10, eta=10.0 run to investigate the effect of the Mach number. The aspect ratio is 3.0, the resolution and computational requirements are the same as above. Curiously, the behavior is not very different from the AR=1.5 run. The parameters are in Run 9 .

  1. Picture 1 (141K)
  2. Picture 2 (114K)
  3. Animation (650K)
M=3.5;
Run 13;
Animation 		We investigate the effect of open boundaries in Run 5 by conducting it in a domain with outflow Boundary Conditions. The results are very different as seen in the animation. The parameters are those of Run 13 . We re-check by using double-precision for Run5 (Run 15).

  1. Animation (Run 13) (400K)
  2. Animation [single precision] (Run 5) (500K)
  3. Animation [double precision] (Run 15) (500K)
M=10;
Run 19;
Animation 		We investigate the effect of open boundaries in Run 8 by conducting it in a domain with outflow Boundary Conditions. The results are very different as seen in the animation. The parameters are those of Run 19 .

  1. Animation (Run 8) (400K)
  2. Animation (Run 19) (500K)
  3. Animation (Later part; frame 60-86) (Run 19) (500K)
  4. Interfacial Circulation (Open v/s Closed Boundary) (11K)
Constucted by Jaideep Ray (jaray@nubis.rutgers.edu)
03/03/97