Floor Section Research Articles

ОБОСНОВАНИЕ КОНСТРУКЦИИ КРЫТОГО ГРУЗОВОГО ВАГОНА С УВЕЛИЧЕННЫМ ОБЪЕМОМ ГРУЗОВОГО ПОМЕЩЕНИЯ

The market of covered freight cars, as well as existing designs of this car type of domestic and foreign production is analyzed. Promising trends of making innovative designs of freight cars for the transportation of piece and container goods are found out. The original design of a covered freight car with an increased body space due to the use of the space between trucks is proposed. To reduce the complexity of loading and unloading operations, sliding sections of the side walls and roof are provided in the car design. To confirm the compliance of the proposed design with the requirements of regulatory and technical documents, the car was entered into the dimension, checking for automatic coupling at the junction of a straight line and a curve, passage in the coupling of an s-shaped curve and coupling of a straight line and a curve, and a single car along a circular curve of a small radius, as well as passing without self-decoupling of the hump of the sorting slide, the ramp exit of the train ferry. A safety assessment is carried out with regard to rolling the wheel onto the rail and overturning the car in curves. The car dynamic characteristics are found out by mathematical modeling methods. The assessment of the strength of the body load-bearing structure, lifting mechanisms of the floor sections, sliding sections of the roof and side walls is performed using the finite element method implemented in the environment of a specialized software package. The results obtained as a result of calculations and computer modeling confirmed the operability and safety of the proposed design of a covered freight car with an increased loading space.

Planning, Designing and Estimation of G+2 Residential Building using Autocad and STAAD PRO

Abstract: This paper presents a comprehensive methodology for the planning, design, and estimation of a G+2 residential building utilizing AutoCAD for architectural drafting and STAAD.Pro for structural analysis and design. The process involves several key stages including site analysis, conceptual design, detailed architectural planning, structural analysis and design, and cost estimation. The initial phase involves site analysis to understand site constraints, orientation, and surroundings, followed by conceptual design to establish the building layout and spatial arrangement. AutoCAD is employed for creating detailed architectural plans, including floor plans, elevations, and sections, ensuring compliance with local building codes and regulations. Subsequently, structural analysis and design are performed using STAAD.Pro, incorporating factors such as loads, material properties, and structural elements. The software facilitates the analysis of various structural systems and helps optimize the design for efficiency and safety. Finally, the estimation phase involves quantifying materials and labor costs based on the finalized architectural and structural designs. This includes itemized lists of materials such as concrete, steel, bricks, and finishing materials, as well as labor costs for construction activities. The proposed methodology integrates AutoCAD and STAAD.Pro to streamline the planning, design, and estimation process for G+2 residential buildings, offering efficiency, accuracy, and adherence to regulatory requirements. The approach presented in this paper serves as a valuable guide for architects, engineers, and construction professionals involved in similar projects

3D Laser Scanning and UAVs in cultural heritage: The case of Old Navarino castle in Pylos, Greece

The archaeological site of Palaiokastro (Old Navarino castle), is located in Messenia on the Coryphasium peninsula, at the southern end of the beach of Voidokoilia in the Navarino Bay, SW Peloponnese. Palaiokastro was built during Frankish rule of the Peloponnese, in the 13th century, over the classical Acropolis of Pylos.The aim of this study is the initial documentation of the current situation of the medieval castle of Palaiokastro applying innovative technology including terrestrial laser scanner (TLS) and unmanned aerial vehicles (UAVs). TLS and UAV photogrammetry have been used in an integrated design to rapidly facilitate the acquisition of the whole gate, eliminating all possible occlusions. TLS was exploited for the acquisition of the facades while the UAV was used to capture the top view of castle gate. The recent improvement of the post-processing algorithms provides us with the ability to implement fusion methods of TLS and UAV models and also deliver an accurate 3D model of the whole gate.The combination of photogrammetry from the UAV with the data of the terrestrial laser scanner was used in order to give us a multitude of products such as textured 3D model, orthophotos, 2D floor plans, elevations and sections which are necessary for the complete and accurate geometric documentation of the current situation of the Southwest gate of Palaiokastro Castle. The various products mentioned assist in the better management of the study data and identification of the different construction phases of the South Gate.

SCIENTIFIC REFERENCE MODEL – DEFINING STANDARDS, METHODOLOGY AND IMPLEMENTATION OF SERIOUS 3D MODELS IN ARCHAEOLOGY, ART AND ARCHITECTURAL HISTORY

Abstract. In object-oriented historical research the need to combine hypotheses and textual arguments with the critical analysis based on sources – such as floor plans, sections, perspectives, and photographs – has considerably benefited from the developments in Digital Humanities (Münster, 2022). The use of digital 3D models has overcome many limitations inherent to two-dimensional records. Since the early 1990s hypothetical 3D reconstructions have therefore increasingly become routine research tools and essential means of representation capable of offering new methods of investigation, enabling new insights into the object-related research. In terms of a holistic approach to the analysis and case studies, i.e. the enhanced ability to examine and explore (Favro, 2012) serious challenges remain regarding documentation, interoperability and long-term access to 3D-based research outputs.In this context, numerous initiatives and research projects have emerged with the common objective of systematising and rationalising the various problems identified by scholars. Such projects still tend to remain isolated, lacking a significant impact on the community of potential users. 3D research outputs are not widely applicable, due to the complex prototypes of the software architecture, difficult to apply in a broad sense. Furthermore, the ‘old’ problems still exist, i.e. the traditional approaches - which do not consider a 3D model as a scholarly result, but only an investigative tool - and the reluctance to share these results and the associated procedures. Therefore, an attempt is being made to define the development and evaluation of an applicable methodology for the hypothetical 3D historical reconstruction, based on a shared theoretical approach.The working method presented here reflects many years of engagement with source-based hypothetical 3D reconstruction of no longer extant or unrealised architecture for teaching and research. Our focus is therefore on a low-threshold, application-oriented method of the Scientific Reference Model (SRM) as a documented and published basic model. The structured SRM represents an important working and knowledge state, which clarifies the essential information about the object, its components, its credibility or extent of hypothesis and copyright. Such SRM is made available for further research, edits and refinement, as well as further derivatives (special applications). Thus SRM represents a findable referential result of a scholarly investigation of a material object that physically no longer exists.

BIM Modelling of the AQP Touristic Cycle Path

BIM (building information modelling) has led to substantial improvements in all design steps. Applied mainly as an information management system in the digital design of structures and buildings, only in recent years has the use of BIM also extended to the construction of road infrastructure. The so-called I-BIM (infrastructure building information modelling) methodology supports the designer in the phases of construction and execution of the design considering all aspects related to the project, including sustainability. Through the software “Roads” of “SierraSoft S.r.l.”, in this article, the I-BIM approach has been used to design a 35 km cycle path as sustainable as possible. From an operational point of view, the design of a cycle path section begins with the modelling of the infrastructure in all its aspects: a study of the route, analysis of interference, modelling of the infrastructure (floor plan, profile and sections) and an intersection study. Creating an infrastructure that increases soft mobility vehicles through a comprehensive design, attracting as many users as possible, is the real innovative challenge.

Structural design of hybrid steel-timber buildings for lower production stage embodied carbon emissions

Using cross laminated timber (CLT) floor panels in combination with steel framing has been identified as a promising new structural configuration that can reduce the embodied greenhouse gas emissions of buildings. This project evaluated efficient structural design of hybrid steel-timber floor sections for a wide range of design parameters to determine the reductions in global warming potential possible relative to a conventional steel-concrete cross section. Each of the structural designs was checked for strength limit states, deflection, and minimum fire rating of either unrated, 1-h, or 2-h for a range of deck spans between 2.3 m and 4.6 m and beam spans between 5.5 m and 13.5 m. For an unrated floor assembly there is little global warming potential benefit to use steel-timber floors if a topping slab is included on top of the CLT slab. Whereas, using steel-timber configurations without a topping slab result in the largest global warming potential reductions. For the 1-h and 2-h ratings, even steel-timber configurations with a 64 mm thick topping slab had up to 20% reduction in global warming potential compared to the steel-concrete alternative. Additionally, several considerations that can drastically affect the global warming potential results were discussed. The results from this project demonstrate the best practices for structural design of hybrid steel-timber buildings to reduce global warming potential of the superstructure frame by between 5% and 35% relative to conventional steel and concrete construction.

Study the influences of ethnic Han and ethnic Bai on Jidi village’s modern Tibetan dwellings in Shangri-La, China

ABSTRACT Chinese ethnic dwellings have recently undergone numerous changes under the influence of economic growth, thus provoking discussions on the relationship between traditional inhabitation and modernization. This paper aims to investigate the effects of modernization on Tibetan residences from the perspective of Shangri-La’s unique multi-ethnic cultural milieu. The research was undertaken in Jidi Village, a traditional Tibetan settlement where the Matsutake industry has enabled residents to reconstruct traditional Tibetan structures by upgrading the local economy. Floor plans and section maps were drawn and analyzed based on a survey of residential buildings in Jidi village. Variations in construction and living situations were confirmed after interviews with Jidi locals. The results indicate that the horizontal distributions of Tibetan residential houses gradually transformed into a courtyard style in the past decades. Furthermore, we concluded that ethnic Han affected contemporary construction materials of Tibetan, whereas ethnic Bai influenced the architectural layouts and designs of architectural components through artisans’ techniques. This study emphasizes the need to cultivate ethnic craftspeople, such as Tibetan artisans in the Shangri-La region, whose numbers are declining due to modernization.

Low-frequency vibration of a timber joist floor section connected by metal screws: experimental validation of FEM models

The structural dynamics of a timber floor junction (six pieces of chipboard plate screwed to a single timber joist) have been investigated experimentally in a frequency range up to 200Hz. Experimental Modal Analysis (EMA), transfer mobilities and velocity level ratios between the chipboard walking surface and the joist were measured with 12 or 24 screw connections between the joist and the chipboard. These experimental data were used to validate Finite Element (FE) models that focussed on the interaction between the chipboard and the joist due to the screws. The aim is to develop validated FE models for timber floors that can be used to assess heavy impacts (such as the rubber ball impact source) and act as a reference for the future development of TSEA models for lightweight structures. The screws were modelled using both rigid connections and springs. For the latter, each point connection was modelled by four springs with stiffness (three coordinate directions and one rotational direction), with model updating using a Deep Neural Network (DNN). A comparison of mode frequencies and mode shapes from EMA and FEM will be made along with forced vibration of the structure.

Objective criteria for choosing an operative approach in case of orbital floor fractures

The aim of the study Id to determinate of objective criteria for the choice of operative access in fractures of the lower wall of the eye socket. As an objective assessment of surgical approaches, the magnitude of the surgical action and the wound depths are used. Computer modeling of transorbital and transantral surgical approach is performed on 390 eye sockets based on computed tomograms with a virtual representation of the eye structure of fractures of the anterior, middle and posterior parts. In case of orbital floor fractures in the anterior part, both transorbital and transantral approaches have satisfactory indicators of operational impact. For fractures in the posterior part, the transorbital approach in the overwhelming majority of cases shows unsatisfactory parameters of objective criteria. For fractures in the middle part, the transantral approach shows the better parameters. The parameters of transorbital access in this case can be considered satisfactory, however, in orbital floor fractures of the middle part, in order to place the implant on undamaged areas of the bone, access to the posterior part of the orbital floor is also required, which leads to unsatisfactory indicators of transorbital access in this situation. For fractures in the anterior orbital floor sections, both transorbital and transantral approaches can be used, and for fractures in the middle and posterior parts, the transantral surgical approach is preferable. In case of accompanying trauma of the medial orbital wall and an anterior part of the orbital floor, transorbital access is preferable, and in the case of the same accompanying injury, but with a fracture of the posterior part of the orbital floor, a combined approach from the orbit and maxillary sinus can be used.

New-generation synthetic implants for the surgical correction of pelvic organ prolapse and stress urinary incontinence: design and testing

Introduction. Up to 50.0% of postpartum women experience stress urinary incontinence (SUI) and pelvic organ prolapse (POP). One of the most common and pathogenetically substantiated methods for surgical correction of severe SIU and POP is prosthetic reconstruction of the pelvic floor, involves the use of monofilament polypropylene surgical meshes through vaginal or laparoscopic access.. However, this way is associated with specific problems, i.e., primarily mucosal erosions, and pelvic pain. This has served as a trigger for the development of new materials that reduce the likelihood of such side effects.Objective. To develop the new-generation synthetic implants for surgical correction of stress urinary incontinence and pelvic organ prolapse.Materials and methods. The main development stages: 1. design of an experimental sample of a synthetic implant (evaluation of basic, physical and mechanical properties). 2. test of an experimental sample obtained in vitro.Results. A bioresorbable polypropylene ligature delivery system was developed and manufactured in two variants: for the POP correction (mesh tape with a width of 13 – 15 mm) and for the SUI correction (mesh tape with a width of 10 – 11 mm).Conclusion. Based on the results of the in vitro tests, we can conclude that the synthetic implants developed are able to provide physiological longitudinal (axial) support of the necessary pelvic floor sections and reduce the risk of postoperative complications. Further in vivo studies are required to assess the response of living tissue to the implantation of this type of synthetic implants.

Performance-Based Solutions of Thermal and Smoke Control Ventilation in Industrial Power Plant Buildings

Industrial power plant buildings differ from all other types of buildings, mainly due to their significant heights and volumes without internal floor sections, exceptionally heat gains during daily work, and potentially high fire risk. Those buildings consist of boiler and turbine houses with multilevel stairways. This complicated architecture creates an extraordinary natural thermal stack effect, causing special ventilation and smoke control systems requirements, adapted to their specific structures and internal conditions. The paper demonstrates a proposal for optimal thermal smoke control ventilation solutions in industrial power plant buildings designated on the basis of performance-based calculations and confirmed by CFD simulations. It demonstrates the possibilities of using daily ventilation in the boiler houses in a function of smoke control systems in the event of a fire and defines fundamental rules for designing the system. Additionally, a new method of sufficient staircase (pylons) protection with a modified pressurization system is proposed.

Experimental Analysis on Mechanical Characteristics of Foundation Soil in Rift Valley Area of Kenya Nairobi-Malaba Railway

The Rift Valley section of Kenya Nairobi-Malaba Railway locates in the Great Rift Valley of East Africa, with complex engineering geological conditions and well-developed geological structures. During the rainy season from March to May 2018, four large-scale ground fissures were formed in the first-stage project of the Nairobi-Malaba Railway of the valley floor section, accompanied by uneven surface settlement and trenches, seriously endangering the safety of the railway and its nearby projects. Through field investigation, it is preliminarily considered that the main reason induced ground fissures and surface settlement is the underlying soil layer being eroded by groundwater. The gully is further formed by surface water erosion on a base of uneven surface subsidence. The geological exploration trench at DK77 ground fissure revealed that the overlying soil layer is respectively grayish-yellow silty clay, cyan-gray volcanic ash, and brownish-yellow silty clay from top to bottom, and the underlying bedrock is volcanic tuff with wide cracks. The fluid flows out or into the bedrock through the cracks developing channels for groundwater up-down flowage. Under the erosion of groundwater to the underlying soil, this study proved the possibility of the occurrence of uneven settlement. When exposed to the groundwater, the underlying soil will exhibit special physical and mechanical properties which are conducive to the occurrence of ground cracks and subsidence. The conventional geotechnical tests are conducted for the three types of overlying soil, and the results reveal the causes of ground fissures and surface settlement from the physical and mechanical properties of the overlying soil and provide a basis for the further qualitative analysis of the mechanism of ground fissures and surface settlement.

Wind Tunnel Installation Effects on Japan Aerospace Exploration Agency’s Standard Model

This paper investigates the interference effects of wind tunnel floor and walls on the Japan Aerospace Exploration Agency’s High-Lift Configuration Standard Model (JSM) as an extension to a paper published in the Journal of Aircraft, Vol. 56, No. 3, May–June 2019, pp. 1080–1098. An unstructured hybrid grid generator, MEGG3D, was applied to JSM wing–body and wing–body–nacelle–pylon configurations to generate grids for free-air flow conditions. These grids were then reused in an investigation of the interference effects of Japan Aerospace Exploration Agency’s low-speed wind tunnel walls to better compare the computational results, both with each other and with experiment. The geometry of the wind tunnel used in our computational simulations is described in detail so that they can be reproduced. A Reynolds-averaged Navier–Stokes flow solver for unstructured hybrid grids, the Tohoku University Aerodynamic Simulation (TAS) code, was used for the simulations. The computational results indicated that the standoff and test section floor boundary layer significantly affected the aerodynamics of the JSM at high angles of attack. Better agreement with experiment was observed for the wing–body configuration in the aerodynamic characteristics near maximum lift if the effects of the standoff and floor boundary layer were considered.

Vibration performance of timber-concrete composite floor section –verification and validation of analytical and numerical results based on experimental data

ABSTRACT Vibration performance of a one-way simply supported timber-concrete composite (TCC) floor section has been studied using analytical as well as numerical methods. Focal points have been verification and validation of results from analytical and numerical calculations of vibration response based on experimental data. For the analytical calculations, floor bending stiffness and vibrational response are determined from methods proposed in the current and revised versions of Eurocode 5. The numerical calculations based on the finite element (FE) method are done using 3D solid elements with orthotropic material parameters. When comparing the results of the FE analysis, better agreement with the experimental data is reached for the fundamental frequency when 3D solid elements are used rather than 3D beam elements. Furthermore, better agreement with the experimental data is reached for RMS acceleration by FE analysis rather than the method based on Eurocode 5. For detailed analysis, the authors suggest performing dynamic FE analysis and calculating vibration response from the TCC floor’s modal responses as eigenmodes and natural eigenfrequencies below 40 Hz. For future studies, it is recommended that the verification of vibration response may be accomplished by applying standard EN 16929.

Exploring potential impacts for early involvement of interior design in the early land development stage - Studying Taiwan Cosmos Group’s hotel development

ABSTRACT The aim of this paper is to promote the importance of interior design during the early land development stage so that unnecessary design revisions and extra construction costs and time could be avoided. Traditionally, procedural architectural and interior conceptual design proposal is often used by developers when applying the land development permit. Due to land development financing and time pressure, this procedural design proposal often contains the brief site and floor plans, elevations, sections, and information to meet the local planning and regulation. However, after the license has been obtained, the discrepancies between submitted procedural design and actual functions are often identified by the hotel development stakeholders, hence revisions and extra costs are required. To explore the potential impacts of it, 48 semi-structured and unstructured interviews have been conducted. The process revealed how group experience helped decision-making at various stages of land development, design, construction, operation management and the potential impacts of traditional land development process. The results showed that the early involvement of interior design with hotel development and operational teams will enable an integrated design and production delivery process, a sustainable hotel development and efficient financing can then be achieved and applied to the future similar practice.

Performance evaluation and strengthening of reinforced concrete buildings

In view of the past earthquakes, it is stated that several structures are located in active seismic zones around the world. So, improvement of the earthquake performance levels of the existing buildings by using various strengthening methods has been the major interest in structural engineering. Non-linear analysis procedures that are defined in several seismic codes exhibit reliable results in the evaluation of seismic performances of existing buildings. In this study, seismic performances of three, five and eight storey existing and strengthened reinforced concrete buildings having the common floor plan, material and section properties of the structural members are investigated according to Turkish Building Earthquake Code-2018 and American Standard, ASCE. To obtain the earthquake performance results of reinforced concrete buildings, displacement demands of the buildings have been obtained and utilized in nonlinear analyses. SAP2000 structural analysis software is used in the solutions. The determined strengthening techniques are provided by adding concentric steel bracing members to existing reinforced concrete buildings and jacketing of the determined columns. As a result of non-linear analyses applied to the existing and strengthened buildings, damage situations of the structural members are determined, seismic performances of the buildings are evaluated according to both codes and the results are interpreted in the end.

Reconstruction of Nineteenth-Century Channel Patterns of Polish Carpathians Rivers from the Galicia and Bucovina Map (1861–1864)

Historical maps are often the only source of information allowing for the regional reconstructions of river channel patterns in the past. In the Polish Carpathians, analyses of historical channel patterns were performed mostly in river reaches scale. In this paper, the Galicia and Bucovina map (1861–1864) (the Second military survey of the Habsburg Empire) was used to reconstruct and map the historical channel patterns of seven rivers from the Polish Carpathians. It was found that, in the nineteenth century, rivers in the western part of the study area (Soła, Skawa, Raba, Dunajec) supported a multi-thread channel pattern, whereas rivers in the eastern part (Wisłoka, San, Wisłok) present a mostly single-thread channel pattern. These differences probably result from the higher relief energy and precipitation, lower proportions of forests in the catchments, and more frequent floods favouring high sediment supply to the fluvial system, and thus the formation of multi-thread reaches in the western part of the study area. At the local scale, the most important factor supporting multi-thread channel pattern development was the availability of gravel sediments in the wide valley floor sections. The formation of anabranching reaches with a single mid-channel form was probably associated with the channel avulsion process. There is no clear evidence linking the change in the channel pattern type with an abrupt change in the river channel slope. This study confirms the usefulness of the second military survey map of the Habsburg Empire for the regional reconstruction of river channel pattern types.

Maximum likelihood estimation for passive energy-based footstep localization

Smart living spaces gather real-time sensor data and use the data to infer, predict, and make decisions. One important way of informing smart living systems is by localizing and tracking occupants. This paper utilizes floor vibration data generated by occupant footsteps—captured by a network of underfloor accelerometers—for passive occupant localization and tracking. A novel maximum likelihood (ML) footstep location estimator is proposed, based on received signal strength/power (RSS) at each sensor location. Localization error variance analysis related to sensor layout (a form of geometric dilution of precision) is studied through deriving and analyzing the theoretical Cramér–Rao lower bound. The proposed localization method does not require knowledge of floor properties, propagation velocity, nor damping. Occupant path tracking is achieved via a Kalman filtering scheme, assuming that an occupant has a zero-mean acceleration. The proposed ML localization method is evaluated using Monte Carlo simulations and using single-occupant walking experiments for 2 different test subjects on a 16 m × 2 m instrumented floor section. Results show superiority of the proposed method to previous RSS footstep localization methods.

A probabilistic simplified Seismic Model from Ambient Vibrations (SMAV) of existing reinforced concrete buildings

SMAV (Seismic Model from Ambient Vibrations) is a mathematical model for predicting the seismic response of an existing building subjected to earthquake that produces no severe damage. The model is based on the identification of the building experimental modal parameters from ambient vibration together with few information about its geometry and constructive typology. The dynamic response of the structure is obtained by a modal superposition where all the inertial properties are concentrated in the center of gravity of the floors or floor sections. The non-linear behavior, which typically occurs during even nondestructive earthquakes, is considered by assigning appropriate laws of variation to the natural frequencies as the deformation increases.This paper presents the development of SMAV to reinforced concrete frame buildings with infill walls and the application to real cases. Specific Frequency Shift Curves (FSCs), that relates the vibration amplitude to the variations of the natural frequencies, have been developed. Such FSCs are a fundamental feature of SMAV, because they allow the seismic nonlinear behavior to be simulated through an equivalent iterative linear analysis. Therefore, in order to comply with the declared aim, in this work the attention is focused on the definition of a suitable simplified model for the generation of FSCs, valid for reinforced concrete frame buildings with infill walls. In the adopted model the global behavior of the infilled frame is simulated by considering the two components of the system, i.e the bare frame and the infill masonry panel, as working in parallel. The mutual interaction between them is modeled by suitably modifying the collapsing mechanism of the masonry panel. The stochastic approach for modeling the seismic response of infilled RC buildings, considering different kinds of infills and taking account of the nonlinearity which arises during a seismic event, is illustrated in detail. The validation of the FSCs has been performed by using the experimental seismic response of buildings as recorded by permanent accelerometric monitoring systems. Finally, two case studies related to the seismic response recorded on a regular and an irregular building, respectively, are presented by comparing the computed end experimental seismic dynamic responses, in order to prove the SMAV ability in reproducing the behavior of RC infilled frame buildings subjected to nondestructive earthquakes.

Experimental investigation of supersonic turbulent flow over cylinders with various heights

The unsteady flow structures and pressure fluctuations of the cylinder-induced shock wave/boundary layer interactions (SBLIs) were investigated at Mach 3.4 and 3.8. The cylinders were mounted on the test section floor with a turbulent boundary layer, and six cylinders with various heights have been tested. The nanoparticle-based planar laser scattering (NPLS) flow visualization tests were performed, and the different features of shock systems as well as the "breath" effects of the separation bubble, have been validated by NPLS images. Dynamic pressure transducers were used to characterize the pressure fluctuations, and a remarkable spectra change was noticed around the cylinder foot. With increasing height, the PSD curve of x/D = − 1 ahead of the cylinder shaped from one-peak pattern to two-peaks pattern, while the second frequency peak showed a typical frequency of f ≈32 kHz. It was inferred that the first peak was more influenced by the free end of the cylinder and the detached shock. The second peak pattern of f ≈32 kHz was presumed to be affected by the vortex breakdown near the cylinder foot through analysis of flow visualization. Low frequency around 0 ~ 3 kHz was found to have an obvious rise at x/D = − 2, close to the typical frequency of SBLIs.