viva correction statements

* List of amendments
| No. | Location     | Amendments                                                                                                                          |
|   1 | ch1, P1      | explain the term 'modern renewables'; distinguish wave and tides energies and corresponding devices                                 |
|   2 | ch1, P2      | delete figures about wave energy converter (fig. 1.2 in the previous version thesis)                                                |
|   3 | ch1, P5      | highlight tide current is important, and specify the frequencies of waves, wind-waves have much shorter time scale,                 |
|   4 | ch1, P6      | highlight contributions                                                                                                             |
|   5 | ch2, P19     | add literature on dual rotor                                                                                                        |
|   6 | ch2,P17      | add references                                                                                                                      |
|   7 | ch3, P23     | add references to BEM method                                                                                                        |
|   8 | ch3, P24     | add 1D momentum and Euler' turbine equations, i.e. eqs. 3.1-3.5; 3.16-3.19                                                          |
|   9 | ch3,  P25    | add explanation on C_n, C_t                                                                                                         |
|  10 | Ch3, P26     | add more texts to explain Fig.3.2                                                                                                   |
|  11 | ch3, p27     | better explanation on Unsteady BEM                                                                                                  |
|  12 | ch3, P30,31  | delete unrelated term in equations of turbulence models, add Eq. 3.47                                                               |
|  13 | ch3, P32     | better format   for formula                                                                                                         |
|  14 | ch4, p40     | add text to explain Fig.4.7                                                                                                         |
|  15 | ch4, P41     | add Fig4.7, show c_p and C_T from URANS and RANS                                                                                    |
|  16 | ch4, p42     | add references for Burton and implicit models                                                                                       |
|  17 | ch4, p48     | delete results from others, and highlight results and contribution                                                                  |
|  18 | ch5, P49     | add periods to tides                                                                                                                |
|  19 | ch5, P58     | explain the reason for the discontinuity of streamlines on interface                                                                |
|  20 | ch5, P59     | better explanation on local aoa                                                                                                     |
|  21 | ch5, p68     | add assumption of the stalled blade model                                                                                           |
|  22 | ch5, P69, 70 | add blade profiles;  add URANS as further research                                                                                  |
|  23 | ch6, p72     | explain the origin of z coordinate                                                                                                  |
|  24 | ch6, p74     | explain how to determine time step size                                                                                             |
|  25 | ch6, p76,77  | add velocity contours from RANS, Fig. 6.5, and 6.6                                                                                  |
|  26 | ch6, p78     | Fig.6.8b is corrected, explain power spectra of C_T, Fig.6.12 and 6.13                                                              |
|  27 | ch6, p79     | more explanation on the harmonic seen in Fig.6.11                                                                                   |
|  28 | ch6,  p82    | change LES to RANS in the further research recommendation                                                                           |
|  29 | ch7, p83     | reduce text size in  the summary, highlight my contribution,  delete results from previour work, such as " it was already seen ..." |
|  30 | ch7, p84     | change verb tense, rewrite the sentences                                                                                            |