OVERVIEW OF THE NUMERICAL

WAVE PROPAGATION MODEL

MILDWAVE

VAKGROEP CIVIELE TECHNIEK

AFDELING WEG- & WATERBOUWKUNDE

ir. Vicky Stratigaki

prof. dr. ir. Peter Troch Hydrodynamica van de kustzone EXERCISE-3

Tuesday 26 November, 2013

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.2

PRESENTATION OVEVIEW

A. short overview of the applications of the model

B. demonstration of the programme using the demo version for the calculation of wave penetration into the harbour of Zeebrugge

C. short overview of performed calculations using MILDwave (willbe presented on 10 December)

presentation overview MILDwave Demonstration:Zeebrugge Examples

MILDWAVE CHARACTERISTICS [1/2]

• time domain numerical wave propagation model (tijdsdomeinnumeriek golfvoortplantingsmodel)

• it solves the depth integrated mild-slope equations of Radder &Dingemans (1985) (lost de diepte-geïntegreerde “mild-slope”vergelijkingen op)

• it solves wave elevations, eta, (verheffingen) and velocity potential,phi (snelheidspotentiaal).

MILDwave Demonstration:Zeebrugge Examples

2 2

g g Bg

k CC CC

t g g

gt

DW

E

ωη φ φ η

φη

−∂= − ∇ ⋅ ∇

∂

∂= −

∂

− +

η surface elevation [m2/s]φ velocity potential at SWL [m2/s]g gravitational acceleration [m/s2]k wave number [rad/m]ω angular frequency [rad/s]C phase velocity [m/s]Cg group velocity [m/s]DB dissipation due to wavebreakingE wave energyWg wind input

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.3

MILDWAVE CHARACTERISTICS [2/2]

• transformation of linear waves above mild slopes and not abruptlyvarying bathymetries, where physical processes such as: reflection,refraction, diffraction, shoaling, transmission and wave breaking, areimportant.

• the model is developed by prof. Peter Troch (1998) and is usedwithin the research group of Ghent University, the past 15 years.

• 1D-numerical wave flume and 2D-numerical wave basin available.

• fine grid sizes can be used to model complex bathymetries

• MILDwave can generate regular and irregular long- and short-crested waves

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.4

MILDwave Demonstration:Zeebrugge Examples

WAVE GENERATION AND ABSORPTION [1/1]

LCW Long-Crested Waves

‣ Wave generation technique‣ the term

is added to the wave generation line (Lee & Suh,

1998)

‣ JONSWAP spectrum S(f)Based on Hm0 and Tp

‣ “single summation model” for

θηη sin2*

y

tCei ∆

∆=

iη

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.5

MILDwave Demonstration:Zeebrugge Examples

MILDWAVE SIMULATION RESULT [1/1]

LCW SCW

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.9

MILDwave Demonstration:Zeebrugge Examples

APPLICATIONS OF MILDWAVE [1/1]

• Typical applications of the model:

- wave transformations;

- wave penetration into harbours;

- design of breakwaters;

- diffraction around hard structures;

- study of wave energy converters and power production

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.10

MILDwave Demonstration:Zeebrugge Examples

DIFFRACTION THROUGH THE GAP OF THE

BREAKWATERS IN ZEEBRUGGE : DEMONSTRATION

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.11

MILDwave Demonstration:Zeebrugge Examples

MILDWAVE PREPROCESSOR – OPEN AND LOAD INPUT FILES [1/1]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.12

STEP 1 STEP 2 After filling in all input values

After “Save settings”

After “Creatct&d file”

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [1/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.13

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [2/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.14

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [3/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.15

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [4/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.16

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [5/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.17

MILDWAVE INPUT FOR REGULAR WAVES - PREPROCESSOR [6/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.18

Disturbance coefficient, kd = Hp/HGB, where H p is the wave height at a point and H GB

the input wave height at the wave generation boundary.

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [1/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.19

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [2/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.20

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [3/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.21

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [4/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.22

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [5/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.23

MILDWAVE INPUT FOR IRREGULAR WAVES - PREPROCESSOR [6/6]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.24

Disturbance coefficient, kd = Hp/HGB, where H p is the wave height at a point and H GB

the input wave height at the wave generation boundary.

MILDWAVE CALCULATOR – OPEN AND LOAD INPUT FILES [1/1]

Dept. of Civil Engineering: Vicky Stratigaki en Pet er Troch p.25

STEP 1

STEP 2

STEP 3

LAST STEP (completed simulation100%)

OVERVIEW OF THE NUMERICAL

WAVE PROPAGATION MODEL

MILDWAVE

VAKGROEP CIVIELE TECHNIEK

AFDELING WEG- & WATERBOUWKUNDE

ir. Vicky Stratigaki

prof. dr. ir. Peter Troch Hydrodynamica van de kustzone EXERCISE-3

Tuesday 26 November, 2013