SMS:CGWAVE Test Cases

The following test cases are available with grids, input, and output files for the user to familiarize himself/herself with.

Test cases are available here with grids, input, and output files for the user to familiarize himself/herself. An extensive list of test-cases are also provided by the Coastal and Hydraulics Laboratory [1]. CGWAVE has been validated against these tests (which represents possibly the most rigorous testing for wave models). The model results are compared to lab data or analytical model results. The input and output files are provided. The user is highly encouraged to perform these simulations, alter parameters, etc., so that an examination of the results may help understand what can be expected. At a minimum, we recommend a visual inspection of the results provided. Often real life problems have complex solutions which are difficult to explain or even anticipate. The fact that the model reproduces the correct result in so many cases may enhance the user’s confidence in his/her results, assuming the modeling was performed with due diligence. The test cases can also be used as a teaching tool.

The following tutorials may also be helpful for learning to use CGWAVE in SMS:

• General Section

• Data Visualization
• Mesh Editing
• Observation

• Models Section

• CGWAVE

Tests 1 & 2

These tests involve monochromatic wave propagation over the shoal-slope bathymetry of Berkhoff et al. (1982). Grid has 15 points per wavelength. Parabolic approximation open boundary condition. Test 1 – input amplitudelitude = 1 meter (linear). Test 2 – input amp = 0.0232 meter (nonlinear). Resulting amplification factors along Transect 5 are shown – they match results and data in Demirbilek and Panchang (1998). Wave direction and phases diagram shows largely progressive waves except near the shoal where the waves become multidirectional.

All runs involve no breaking.

Tests 3 & 4

Wave propagation over flat bottom and a shoal, after Vincent and Briggs (1989, JWPCOE). Monochromatic (T = 1.3 s) and broad-directional spectral (BI) input based on Panchang et al. (1990, JWPCOE). For spectral simulation, input consists of 29 directional components in the ±60° bandwidth and 5 frequency components. All runs involve no breaking. Results match numerical and experimental data described in Demirbilek and Panchang (1998), Vincent and Briggs (1989), and Panchang et al. (1990)

Test 5

Wave propagation (T=5.05 s, d = 0.25 meter) over a flat bottom surrounded by infinite ocean. Depth = 0.25 meter. Test 5 – using Bessel-Fourier boundary conditions (this is the most accurate boundary condition for the problem as specified although the exterior conditions are unrealistic in practice). See Xu et al. (1996, JWPCOE) for details. Note the Bessel-Fourier boundary condition works only for input amplitude = 1 meter. For other input amplitudes, solution should be appropriately scaled by user.

Test 6

As in test 5, but with friction which seems to become effective for long waves. Test 6 – the circular domain is assigned f = 0.5 everywhere, waves propagate in from the right. Friction leads to smaller wave heights.

Test 7

As in Test 5, but only the central area has a non-zero friction.

Test 8

Waves propagating towards a coastline on a flat seabed, parabolic and one-dimensional open boundary condition. No breaking or friction used.

Test 9

As in Test 8, but with parabolic boundary condition only. This is used to demonstrate correctness of this boundary condition since solution for constant exterior depth is known.

Test 10

As in Test 8, but friction f = 0.5 for the whole domain. Note wave height input = 2 m. at the end of one-dimensional section which extends beyond the semicircle. Wave heights decrease in shoreward direction due to friction. No breaking used.

Test 11

As in Test 8, but with f = 0.5 in a central square region (can be seen on .cgi file). f = 0 elsewhere. No breaking.

Test 12

As in Test 10, but with central square area indicated as a “floating dock”.

Test 13 - Circular Island/Shoal

Long wave propagation past the circular island/shoal combination of Homma (1950). Bessel-Fourier open boundary condition. Input T = 240 sec. Results match analytical solution given in Demirbilek & Panchang (1998). No breaking.

Test 14

As in Test 5, but with a circular pile in the domain. Input T = 10 s and constant depth = 15.03 meters. Results match analytical solution (see Panchang et al. 2000, ASCE JWPCOE).

Test 15

As in 14, but the pile is off-center. Parabolic open boundary condition. Results match analytical solution (Panchang et al. 2000, JWPCOE).

Test 16

Long wave (T = 260 s) propagation up a sloping beach. Parabolic and one-dimensional boundary condition. Solution is completely one-dimensional. Results match those in Panchang et al. (2000).

Test 17

Oblique wave incidence on uniformly sloping beach. Results match analytical solution of Radder (1979) given in Panchang et al. (2000, JWPCOE).

Test 18

Propagation of obliquely incident waves (incidence angle =20°) past a shore-perpendicular thin fully-reflecting breakwater on a sloping beach (beach is fully absorbing). Parabolic and one-dimensional open boundary condition. Results match analytical results given in Kirby (1986) and Panchang et al. (2000).

Tests 19 & 20

As in Test 18, but with nonlinear breaking on and off. Test pertains parameters in Zhao et al., (2000, Coastal Engineering).

Test 21

As in Test 19, but with shore-parallel breakwater. Parameters and results as in Zhao et al. (2000). Results are for no breaking.

Test 22

As in Test 19, but with shore-parallel breakwater. Parameters and results as in Zhao et al. (2000). Results are for nonlinear breaking.

Test 23

Wave propagation/resonance in a rectangular harbor. Results match analytical solution plotted in Demirbilek & Panchang (1998). With friction f = 0.12, the resonant peak amplification reduces substantially for kl =1.4 (T = 1.0447 s).

Test 24

Wave propagation around a floating square platform in circular domain. While developing the 2-d grid, the area covering the dock is also filled with finite elements; each node is assigned a depth equal to the local under-keel clearance times the correction factor a. The parameters in the simulations are 2a = 2m, h = 1m, d/h = 0.5 and ka = 2 (corresponding to the cases described by Tsay and Liu (1983). So the depth used for calculation = α.d = α.(0.5) = 0.04. Correction factors such as a = 0.08 are given in Li et al. (2005, Canadian J. of Civil Engr). Results are similar to 3d results given in Tsay & Liu (1983).

Test 25

Wave propagation around a circular shoal in a circular domain. This is intended to show the effects of the “steep slope” terms. The test is based on Fig. 7 in Chandrasekhara and Cheung (1997, JWPCOE).

Test 26

Radiation Stress calculations. Waves propagating towards a coastline on a flat seabed, parabolic and one-dimensional open boundary condition. No breaking or friction used. Five folders are given. Three separate monochromatic cases (260 degrees, 270 degrees, and 280 degrees, i.e. normal incidence and 10 degrees off-center incidence) each of amplitude 0.5 m and period T = 1 s, for fully absorbing coastline. For 270 degrees, results for fully reflecting coastline are also given. Results match theoretical solution (eq. 6-9 and eq. 54 in Copeland, 1985, Coastal Engg).

For spectral tests, the same 3 waves were added to form the input spectrum. Radiation stresses for the spectrum are an integration of individual components (eq. 1 in Fedderson 2004, Coastal Engg). The spectral results can be used also to check the mean wave direction (which should be 270 degrees) and the mean frequency ( = 6.28 radians/s).

Test 27

Wave propagates (incidence angle =0°) over a rectangular friction region in a constant-depth domain. With friction f = 2.122, input T = 20s, H = 6.1m and constant depth = 15.2m. Results match solution obtained by Dalrymple et al. (1984).

Test 28

Obliquely incident wave propagates in a rectangular channel with the fully-reflecting side walls. Input T = 12s and constant depth = 8m. Results match analytical solution plotted in Dalrymple and Martin (2000, JWPCOE).

Related Topics

• CGWAVE