Yazar "Unal, Ugur" seçeneğine göre listele

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    An Experimental Investigation of Tsunami Bore Impact on Coastal Structures
    (Mdpi, 2024) Erduran, Kutsi S.; Akansu, Yahya E.; Unal, Ugur; Adekoya, Olusola O.
    This experimental study focused on the measurement and analysis of the impact force caused by a tsunami bore on a coastal structure. The bore wave was produced by a dam break mechanism. The water depth in the reservoir and the location of the coastal structures were varied to simulate different impact scenarios. The time history of the force resulting from the impact of the bore wave on the coastal structure was measured. The propagation of the bore wave along the flume was recorded and the video recordings were converted into digital data using an image-processing technique in order to determine the flow depth variations with time. The hydrostatic forces and the corresponding depth and time-averaged hydrodynamic forces as well as the maximum hydrodynamic forces were acquired for each scenario. The ratio of hydrodynamic to hydrostatic forces were obtained, and it was observed that the calculated averaged ratio was within the recommended design ratio. The results indicate that an increase in the reservoir level caused an increase in the magnitude and intensity of the impact forces, however, the relationship was non-linear. Moreover, it was found that the location of the structure did not play a significant role on the intensity of the impact forces.
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    Experimental and numerical investigation of partial dam-break waves
    (Pergamon-Elsevier Science Ltd, 2024) Erduran, Kutsi S.; Unal, Ugur; Dokuz, Ahmet S. .
    In this study, the partial dam-break wave was experimentally and numerically investigated with regard to the wave speed and pattern for dry and wet downstream bed conditions at two different reservoir water levels. Experimental studies were carried out in a horizontal rectangular cross-section flume with dimensions of 6.0 x 1.2 x 0.5 m. The experiments were recorded and the video recordings were converted into digital data with the help of image processing technique. Hence, both 1 and 2 dimensional propagations of the flood shock wave and the water surface variations with time at the pre-determined points on the reservoir were able to be monitored. The exact gate opening time was acquired by the Arduino system. Flow-3D software and a 2D numerical model were used for the numerical studies. Comparisons were made between the numerical and experimental studies for 1D -2D partial dam-break wave propagations and the pointwise measurement. The satisfactory agreements in terms of the shock and rarefaction wave speed and pattern were observed. The results also indicated that the image processing technique was a promising technique to obtain the experimental outputs.
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    Experimental and Numerical Investigation of the Effect on the Water Surface Profiles of Bridge Pier Type and Skew Angle
    (Konya Teknik Univ, 2023) Erduran, Kutsi Savas; Unal, Ugur; Dokuz, Ahmet Sakir; Nas, Mustafa Cagri
    Design of bridge piers is so much important for the structural safety of bridges, however, at least at the same extent, hydraulic analysis of bridge piers is also required. Bridge piers are structures that obstruct the flow by narrowing the flow area and can cause flooding in the bridge upstream. Therefore, with the light of numerical and experimental studies, accurate estimations of the occurrence of water surface profiles and affluxes resulted from the construction of bridge piers under different flow conditions are the major part of bridge hydraulics. In this study, the effects of bridge piers with four different cross-sections and four different skew angles on the water surface profiles and the affluxes were experimentally and numerically investigated. The experimental study has been conducted in a flume with dimensions of 10x0.309x0.45m in Department of Civil Engineering Hydraulics Laboratory at Nigde Omer Halisdemir University. The experimental measurements were taken using 4 different shapes of bridge piers (square, circular, oblong and ogival upstream face) and 4 different skew angles (0(0), 15(0), 30(0) and 45(0)), and the images obtained from video recordings of each experiment were converted into numerical values using an image processing technique. In addition, commercial package program HEC-RAS software and a direct step method were also used for the numerical modelling and the numerical water surface profiles and affluxes were also obtained for the purpose of comparisons. In the conclusion part, the comments on the applicability of HEC-RAS software and the suitability of the image processing technique were given for the similar problems.