COMSOL Model Report
| Property | Value |
| Model name | |
| Author | |
| Company | |
| Department | |
| Reference | |
| URL | |
| Saved date | Nov 24, 2006 11:05:27 PM |
| Creation date | Nov 17, 2006 4:07:23 PM |
| COMSOL version | COMSOL 3.3.0.405 |
File name: D:\research\ASA Talks\f06\animations\visualizations\diffraction\barrier h=lambda.mph
Application modes and modules used in this model:
| Name | Expression | Value | Description |
| f0 | 25 | frequency | |
| x0 | 2 | ||
| y0 | 2 | ||
| c0 | 200 | speed of sound m/s | |
| rho0 | 1.21 | ||
| p0 | 1 | ||
| t0 | 1/f0 | ||
| lambda0 | c0/f0 | ||
| h0 | 8 | height of barrier | |
| hol | h0/lambda0 | ratio of height to lambda |
| Name | Expression | Description | |
| gt | (t<2*t0)*(-8*pi^2*f0^2*(t-t0)*exp(-pi^2*f0^2*(t-t0)^2)) | gaussian source | |
| gts | sin(2*pi*f0*t) | sinusoidal source | |
| gtc | cos(2*pi*f0*t) | cosine source |
Number of geometries: 1
Space dimensions: 2D
Independent variables: x, y, z
| Number of degrees of freedom | 14816 |
| Number of mesh points | 3758 |
| Number of elements | 7300 |
| Triangular | 7300 |
| Quadrilateral | 0 |
| Number of boundary elements | 216 |
| Number of vertex elements | 12 |
| Minimum element quality | 0.701 |
| Element area ratio | 0.001 |
Application mode type: Pressure Acoustics (Acoustics Module)
Application mode name: acpr
| Name | Variable | Value | Description |
| p_i | p_i_acpr | exp(-1/2*(t-x/cs_acpr)^2/0.01^2) | Incident pressure wave |
| p_ref | p_ref_acpr | 20e-6 | Pressure reference |
| Property | Value |
| Default element type | Lagrange - Quadratic |
| Analysis type | Transient |
| Damping | Off |
| Specify eigenvalues using | Eigenfrequency |
| Solve for | Total wave |
| Symmetry plane x=0 | Off |
| Symmetry type for x=0 | Symmetry |
| Symmetry plane y=0 | Off |
| Symmetry type for y=0 | Symmetry |
| Frame | Frame (ref) |
| Weak constraints | Off |
Dependent variables: p
Shape functions: shlag(2,'p')
Interior boundaries not active
| Boundary | 1, 3 | 2 | |
| Type | Radiation condition | Radiation condition | |
| Pressure source (p0) | Pa | 0 | 0 |
| Inward acceleration (nacc) | m/s2 | 0 | 0 |
| Source location, x coordinate (x0) | m | 2 | 2 |
| Source location, y coordinate (y0) | m | 2 | 24 |
| wavetype | 1 | PL | CYL |
| Boundary | 4-6 | 7 | 8 |
| Type | Sound hard boundary (wall) | Radiation condition | Radiation condition |
| Pressure source (p0) | 0 | 0 | 0 |
| Inward acceleration (nacc) | 0 | 0 | 0 |
| Source location, x coordinate (x0) | 4 | 17 | 4 |
| Source location, y coordinate (y0) | 4 | 8 | 4 |
| wavetype | CYL | CYL | PL |
| Boundary | 9-12 |
| Type | Normal acceleration |
| Pressure source (p0) | 10*cos(2*pi*f0*t) |
| Inward acceleration (nacc) | 1*cos(2*pi*f0*t) |
| Source location, x coordinate (x0) | 0 |
| Source location, y coordinate (y0) | 0 |
| wavetype | PL |
| Subdomain | 1 | |
| Fluid density (rho) | kg/m3 | rho0 |
| Speed of sound (cs) | m/s | c0 |
Solve using a script: off
| Analysis type | Transient |
| Auto select solver | On |
| Solver | Time dependent |
| Solution form | Automatic |
| Symmetric | auto |
| Adaption | Off |
Solver type: Linear system solver
| Parameter | Value |
| Pivot threshold | 0.1 |
| Memory allocation factor | 0.7 |
| Parameter | Value |
| Times | 0:0.005:0.25 |
| Relative tolerance | 0.01 |
| Absolute tolerance | 0.0010 |
| Times to store in output | Specified times |
| Time steps taken by solver | Free |
| Manual tuning of step size | Off |
| Initial time step | 1E-3 |
| Maximum time step | 1E-3 |
| Maximum BDF order | 2 |
| Singular mass matrix | Maybe |
| Consistent initialization of DAE systems | Backward Euler |
| Error estimation strategy | Include algebraic |
| Allow complex numbers | Off |
| Parameter | Value |
| Constraint handling method | Elimination |
| Null-space function | Automatic |
| Assembly block size | 5000 |
| Use Hermitian transpose of constraint matrix and in symmetry detection | Off |
| Use complex functions with real input | Off |
| Stop if error due to undefined operation | On |
| Type of scaling | Automatic |
| Manual scaling | |
| Row equilibration | On |
| Manual control of reassembly | Off |
| Load constant | On |
| Constraint constant | On |
| Mass constant | On |
| Damping (mass) constant | On |
| Jacobian constant | On |
| Constraint Jacobian constant | On |
| Name | Description | Expression |
| Lp_acpr | Sound pressure level | 10 * log10(0.5 * p_t_acpr * conj(p_t_acpr)/p_ref_acpr^2) |
| Lp_s_acpr | Scattered sound pressure level | 10 * log10(0.5 * p_s_acpr * conj(p_s_acpr)/p_ref_acpr^2) |
| p_t_acpr | Total acoustic pressure | p |
| p_s_acpr | Scattered pressure wave | p-p_i_acpr |
| Name | Description | Expression |
| na_acpr | Normal acceleration | nx_acpr * ax_acpr+ny_acpr * ay_acpr |
| nk_acpr | Scalar product between n and kdir | (kdirx_acpr * nx_acpr+kdiry_acpr * ny_acpr)/sqrt(kdirx_acpr^2+kdiry_acpr^2) |
| Name | Description | Expression |
| ax_acpr | Local acceleration, x component | -(px-qx_acpr)/rho_acpr |
| ay_acpr | Local acceleration, y component | -(py-qy_acpr)/rho_acpr |
| Lp_acpr | Sound pressure level | 10 * log10(0.5 * p_t_acpr * conj(p_t_acpr)/p_ref_acpr^2) |
| Lp_s_acpr | Scattered sound pressure level | 10 * log10(0.5 * p_s_acpr * conj(p_s_acpr)/p_ref_acpr^2) |
| p_t_acpr | Total acoustic pressure | p |
| p_s_acpr | Scattered pressure wave | p-p_i_acpr |
| norma_acpr | Local acceleration, norm | sqrt(abs(ax_acpr)^2+abs(ay_acpr)^2) |
| normq_acpr | Dipole source, norm | sqrt(abs(qx_acpr)^2+abs(qy_acpr)^2) |