فهرست مطالب پیمان آق تومان

In this research study, effects of the draught and sheet height in pontoon floating sheet-breakwaters on the transmission and reflection coefficients against irregular sea waves was investigated. The project has been carried out using an experimental method within a wave flume of Soil Conservation and Watershed Research Institute. The incident waves were irregular and the wave spectrum was JONSWAP. The range of wave heights varied between 2 and 12cm and their mean periods were set to be between 0.63 and 1.26 seconds. To investigate the effect of draught in pontoon breakwaters, three experimental model with similar breadth and different draughts of 8, 10 and 12 cm were tested. Also, in order to investigate effect of sheet height in pontoon sheet breakwaters, sheet heights with 8, 16 and 24 cm were examined and compared without sheet case. The water depth was set to be 60 cm. The number of waves for each test was 250.

Reshaping breakwater is a kind of rubble mound structure that its profile reshapes to a equilibrium one after impinging of waves. In This paper, the effects of wave parameters including significant wave height, peak and mean wave periods, storm duration, as well as structural parameters including water depth at the toe of structure, initial slope of the structure, permeability and stone gradation on irregular wave transmission through reshaping breakwaters have been studied and investigated. The present research has been carried out using the results of hydraulic model tests accomplished in the wave flume of Soil Conservation and Watershed Management Center, affiliated to the Ministry of Jihad-e Agriculture, using irregular waves. The results of the research show the variations of wave transmission coefficients versus nondimensional parameters. Moreover, a new relationship has been presented to calculate the coefficients of wave reflection from reshaping breakwaters.

Over the present experimental research, a comprehensive study has been carried out to investigate the effect of the structure's primary slope on the amount of overtopping the irregular waves of the sea from the reshaping rubble-mound seawalls. The experiments of physical modeling of this research have been done in the flume of the Soil Conservation and Watershed Management Research Institute (SCWMRI). The waves applied to the structure model are irregular and the energy spectrum of the applied waves is JONSWAP. To study the slope effect of seawalls, the structure slopes of 1:2.5, 1:2 and 1:1.25 have been tested. The material of armor layer have been regarded with the scale of 1:20 model and grading class of D85/D15=1.82. A number of 1000 waves were applied on the structure over the research in general and some 57 experiments have been totally accomplished. The achieved outcomes of the experiments after drawing the figures were analyzed and the effect of the structure's primary slope on the amount of waves overtopping were investigated. The outcomes indicate that the primary slope enjoys no considerable effect on the amount of overtopping from the reshaping rubble-mound seawalls, although following the fall of the structure's primary slope, the mean overtopping discharge faces with a least decrease.

In the present paper optimum height of skirt of Skirt Pontoon Floating Breakwater arereported by physical model. 54 tests on 3 types (skirt heights: 8,16 and 24 cm) of skirt pontoon floating breakwater is conducted in the wave flume of Soil Conservative and Watershed Research Center. Hydrodynamical and geometrical parameters were analysised. In this research optimum height of skirt to water depth ratio is determined.

In this research, the mechanisms and various behaviours of reshaping berm breakwaters against waves attack have been investigated. These breakwaters are kinds of rubble mound breakwaters which their profiles reach to and equilibrium state after impinging of design waves. This research has een carried out sing laboratory model method in a wave flume. Both regular and irregular waves were sed in laboratory ests. The mechanisms and the behavior of currents inside and outside the structure ere investigated by njecting dye stuff inside it and taking films.

In This paper, the effect of wave parameters including significant wave height, peak and mean wave periods, storm duration; as well as structural parameters including water depth at the toe of structure, initial slope of the structure, permeability and stone gradation on wave reflection from reshaping breakwaters has been studied and investigated. The present research has been carried out using the results of hydraulic model tests accomplished in the wave flume of Soil Conservation and Watershed Management Center, affliated to the Ministry of Jihad- e- Agriculture, using irregular waves. The results of the research shows the variations of wave reflection coefficients versus non-dimensional parameters. Moreover, a new relationship has been presented to calculate the coefficient of wave reflection from reshaping breakwaters.

The berm recession of a reshaping berm breakwater has a very important role in the stability and reshaping of this structure. In this research, the recession of the berm due to wave parameters has been studied based on 2D experimental modeling method in a wave flume. Irregular waves with JONSWAP spectrum were used. A total of 60 tests have been performed to cover the impact of wave parameters such as significant wave height, mean wave period and storm duration on berm recession. A new dimensionless parameter is introduced to evaluate the simultaneous influence of wave height and wave period. Then, a new formula that includes the wave parameters is derived using the new dimensionless parameter for estimating the berm recession. A comparison is made between the estimated berm recessions by this new formula and formulae given by other researchers. The results of this new formula in comparison with the other investigators formula show a proper correlation with the present experimental data and other experimental results.

In this research, the effects of irregular wave action on run-down on the slope of reshaping rubble–mound breakwaters have been investigated. Reshaping breakwater is a new kind of breakwater in which the initial profile is changed to an S-shaped profile, once affected by waves. Therefore, the relations related to run-down levels on conventional breakwaters cannot be used for this type of structure. This research is conducted based on Experimental Modeling. Experiments were performed in the Soil Conservation and Watershed Management Research Institute (SCWMRI) for multiple cross sections of reshaping breakwaters with three different slopes in years 2003 and 2004. The wave flume was equipped with a modern DHI wave generation system, which contains paddle, power pack, hardware and software divisions. The hydraulic responses mentioned above, were investigated by changing the wave parameters such as significant wave height, mean and peak wave period and storm duration on the three structure’s seaward slopes, equal to 1:1.25, 1:2.0, 1:2.5. JONSWAP wave spectrum was used in all experiments. The Armored layer materials were included in three grading classes (Dn85A/Dn15A=1.14, 1.44, 1.82) and a Range of structural index permeability, Pe. In order to investigate the effects of changing structural geometry, wave properties, and the comparison between two scales, 120 tests were performed with 1000 to 6000 waves. Finally the results of different scale factors were compared. The experimental results were plotted as graphs showing the run-down levels versus the surf similarity parameter and deepwater wave steepness. Because the Iribarren number does not accurately describe the combined effects of slope and wave steepness, an improved and new formula was fitted to data using multiple linear regression and nonlinear regression, which results in some new empirical equations presented in this paper.

This paper presents the results of hydraulic model tests on the stability of rubble mound breakwaters with armour layers of antifer cubes. The tests were performed using irregular waves. The effect of wave parameters and the structure slope on the stability of these artificial armour units has been investigated and the stability formulae have been derived. Finally a comparison between these formulae and the stability relationships derived by van der Meer (1988) for cubes has been made.

In this research the irregular wave transmission from reshaping rubble-mound breakwaters have been investigated. Reshaping breakwaters are recent development in breakwater design, which their initial profiles are changed to a (s) shaped after wave impact. Therefore, the usual relations for transmission coefficients on conventional breakwaters cannot be used for this type of structure. A comprehensive experimental research was carried out for many sections of reshaping breakwaters with three different slopes in SCWMRI wave flume equipped with a DID wave generation system. The hydraulic responses of wave transmissions were investigated by changing the wave parameters such as significant wave height, mean and peak wave period and storm duration on three seaward slopes (respectively 1:1.25, 1:2.0, 1:2.5). JONSW AP wave spectrum was used in all experiments. The armor layer materials were used in three grading class (Dn85A/Dn15A=1.14, 1.44, 1.82) and a range of structural permeability, Pe(1£Dn50A/Dn50c£20). IN order to change structural geometry, wave properties and other variables, 100 tests were carried out with 1000 to 6000 waves. The experimental results showed the relation between transmission coefficients and the new parameter R*. An improved and new relation was achieved using multiple linear regressions.