Wind Waves in the Balaklava Bay under Extreme Wind Conditions

Wind waves in bays and harbors have a significant impact on the safety of navigation and operation of the coastal infrastructure. The purpose of this work is to study the characteristics of wind waves in the Balaklava Bay (Crimean Peninsula) under different wind conditions. The study was carried out on the basis of a numerical spectral SWAN wave model using a sequence of nested grids. Specific calculations of waves in the Balaklava Bay are carried out for constant winds of different directions and for an extreme storm emerged in the Black Sea in November 2007. It was found that in the southern part of the bay the most intense waves are formed with southerly winds. At the bay entrance, at wind speeds, which can occur once a year and once every 25 years, the maximum values of the significant wave height hs amount to 3 and 5.4 m, respectively. In the northern part of the bay, the maximum values hs with winds, which can occur once a year and once every 25 years, respectively, are equal to 0.25 and 0.46 m. It was defined that the storm waves penetrating into the southern part of the bay quickly attenuate as they spread through the narrowness to the northern part of the bay. Thus, the local wind field is the determining factor affecting the intensity of waves in the northern part of the Balaklava Bay.

Wind Tunnel Test on Local Wind Field around the Bridge Tower of a Truss Girder

The aerodynamic performance of vehicles on a bridge deck depends on the local wind field, especially in a region near a bridge tower. This study was carried out on a large-scale (1: 20.4) truss girder, and wind tunnel tests were performed to determine how the wind fields were affected by the bridge tower in the presence of different wind barriers. The wind barrier parameters significantly affect the wind field. Wind barriers should be sufficiently high to provide a wide protection range and have relatively small porosities to reduce the wind speed. The opening form of the wind barrier should also be considered, where a circular-holed form reduces the wind speed and turbulence more than a horizontal-slatted form. The wind field is affected by structures and bridge towers on the deck. A turning point in the wind speed occurs at a measurement point near the bridge tower, and this point gradually moves upward towards lanes on the leeward side of the bridge. The equivalent wind speed is significantly reduced over a four-meter height range because of shadowing from the bridge tower and the wind barrier.

Estimation and Modeling of Fluctuating Wind Amplitude and Phase Spectrum Using APES Algorithm Based on Field Monitored Data

The fluctuating wind power spectrum (FWPS) in given specifications could only represent the second-order probabilistic characteristic, which indicates that it is not capable of fully expressing the stochastic wind field. Estimation and modeling of the fluctuating wind amplitude spectrum (FWAS) as well as the fluctuating wind phase spectrum (FWPhS) by using measured wind velocity data can make up for the deficiencies mentioned above. A high-resolution nonparametric spectral estimation algorithm—amplitude and phase estimation (APES)—is used to estimate the FWAS and the FWPhS, using the field measured wind velocity data of a certain cable-stayed bridge in Shanghai, China. An empirical expression (eFWAS) is introduced by dimensional analysis to model the random FWAS, and its specific Davenport form is proposed according to field measured data. The parameters of the Davenport eFWAS model are estimated by using the above measured FWAS, and three specific applications of this model are put forward when different known conditions are met. Compared with the measured FWAS, the stochastic Davenport eFWAS model proposed in this paper can accurately describe the statistical properties of the local wind field and improve the modeling accuracy of the FWAS, which is important in antiwind structural design and safety assessment.

Simulation of Wind Characteristics Surrounding a Container Terminal

Metal structures of present port machineries are much more flexible than those decades ago, and are therefore very vulnerable to various wind-induced vibrations, among which the frequently happened random buffeting of structures attracts some special attentions since it contributes pretty much to the early structural fatigue. The intensity of buffeting is closely related to the local surrounding wind field. In this paper, the local wind field of a container port in Shanghai of China was simulated by CFD technique, and the corresponding spatial distribution of wind velocity, turbulence intensity, and wind profile were investigated in detail.