Experiments in Fluids最新文献_第4页

Three-dimensional flows in the wake of a non-cavitating and cavitating marine propeller 无气蚀和有气蚀船用螺旋桨尾流中的三维流动

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-28 DOI: 10.1007/s00348-024-03888-9

Özge Başkan Perçin, Daniele Fiscaletti, Gerrit E. Elsinga, Tom van Terwisga

{"title":"Three-dimensional flows in the wake of a non-cavitating and cavitating marine propeller","authors":"Özge Başkan Perçin, Daniele Fiscaletti, Gerrit E. Elsinga, Tom van Terwisga","doi":"10.1007/s00348-024-03888-9","DOIUrl":"10.1007/s00348-024-03888-9","url":null,"abstract":"<div><p>Tip-vortex cavitation is among the first forms of cavitation to appear around ship propellers. In the present study, the time-resolved three-dimensional flow field around non-cavitating and cavitating tip vortices in the wake of a marine propeller is investigated with tomographic PIV. The advance ratio of the propeller and the Reynolds number of the flow are kept constant, while the cavitation number is varied by changing the pressure inside the cavitation tunnel. The importance of masking the tip-vortex cavities before performing the tomographic reconstruction is firstly demonstrated, followed by a description of the applied masking algorithm. From the three-dimensional velocity vector fields, coherent structures of vorticity are identified using the <i>Q</i>-criterion. Three types of coherent structures are observed to populate the wake of the propeller, i.e. tip vortex, hub vortex, and secondary vortical structures. The secondary vortical structures surrounding the tip vortex appear to be progressively smaller in size and more chaotically-organized for decreasing cavitation number. This can be attributed to the pressure fluctuations induced by the cavity, which strengthen when the cavity size grows.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142414808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Determination of unsteady wing loading using tuft visualization 利用簇状可视化确定非稳态机翼载荷

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-27 DOI: 10.1007/s00348-024-03882-1

Francis De Voogt, Bharathram Ganapathisubramani

{"title":"Determination of unsteady wing loading using tuft visualization","authors":"Francis De Voogt, Bharathram Ganapathisubramani","doi":"10.1007/s00348-024-03882-1","DOIUrl":"10.1007/s00348-024-03882-1","url":null,"abstract":"<div><p>Unsteady separated flow affects the aerodynamic performance of many large-scale objects, posing challenges for accurate assessment through low-fidelity simulations. Full-scale wind tunnel testing is often impractical due to the object’s physical scale. Small-scale wind tunnel tests can approximate the aerodynamic loading, with tufts providing qualitative validation of surface flow patterns. This investigation demonstrates that tufts can quantitatively estimate unsteady integral aerodynamic lift and pitching moment loading on a wing. We present computational and experimental data for a NACA0012 wing, capturing unsteady surface flow and force coefficients beyond stall. Computational data for varying angles of attack and Reynolds numbers contain the lift coefficient and surface flow. Experimental data, including lift and moment coefficients for a tuft-equipped NACA0012 wing, were obtained at multiple angles of attack and constant Reynolds number. Our results show that a data-driven surrogate model can predict lift and pitching moment fluctuations from visual tuft observations.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-024-03882-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142414558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using the zonal calibration algorithm with adaptive inner boundary to improve the measurement accuracy of five-hole probe 使用带自适应内边界的分区校准算法提高五孔探头的测量精度

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-26 DOI: 10.1007/s00348-024-03883-0

Haideng Zhang, Tangyi Zhang, Yun Wu

{"title":"Using the zonal calibration algorithm with adaptive inner boundary to improve the measurement accuracy of five-hole probe","authors":"Haideng Zhang, Tangyi Zhang, Yun Wu","doi":"10.1007/s00348-024-03883-0","DOIUrl":"10.1007/s00348-024-03883-0","url":null,"abstract":"<div><p>Zonal calibration algorithm is the most widely used method to extend the measurement range of five-hole probes. However, large measurement error will be aroused near the boundary between two neighboring zones and this is acknowledged as the inner boundary measurement problem of zonal calibration algorithm. To tackle this problem, a two-dimensional uniform flow model is developed in this paper to describe the relationship between pressure from holes and flow angles. Based on this model, a method to adjust the boundary between two neighboring zones automatically with respect to inlet flow conditions is developed. With this novel method, the data extrapolation of zonal calibration algorithm at measurement stations near the boundary between two neighboring zones is avoided, and the corresponding large measurement error is eliminated. According to the experimental data, maximum measurement error of total pressure and flow angle can reach 7.5% and 3.2°, and will be reduced to 0.89% and 0.12° by the novel method. Resultantly, the inner boundary measurement problem of zonal calibration algorithm is solved. Influences of several key parameters on the measurement accuracy of the novel method are investigated too, and criteria to adjust the boundary between two neighboring zones are given. Conclusions of this paper can be used to further improve the accuracy of five-hole probes in measuring large angle flows.</p><h3>Graphic abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142414035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Three-dimensional flow features of underexpanded jets emerging from an elliptic convergent nozzle 从椭圆会聚喷嘴喷出的未充分扩张射流的三维流动特征

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-24 DOI: 10.1007/s00348-024-03885-y

Tatsuya Nagata, Takumi Sakashita, Shinichiro Nakao, Yoshiaki Miyazato

{"title":"Three-dimensional flow features of underexpanded jets emerging from an elliptic convergent nozzle","authors":"Tatsuya Nagata, Takumi Sakashita, Shinichiro Nakao, Yoshiaki Miyazato","doi":"10.1007/s00348-024-03885-y","DOIUrl":"10.1007/s00348-024-03885-y","url":null,"abstract":"<div><p>Understanding the fundamental structure of shock-containing elliptic jets is of great academic and engineering interest, but there are still many unknowns. The three-dimensional flow features of an underexpanded jet emerging from an elliptic convergent nozzle with an aspect ratio of 4.0 at the exit face are experimentally investigated by rainbow schlieren tomography (RST). The elliptic jet is discharged into quiescent air using an intermittent blowdown wind tunnel. The Reynolds number based on the equivalent diameter and flow properties at the nozzle exit is <span>(3.0times 10^{5})</span>. Multi-view rainbow schlieren images of the elliptic jet are taken by rotating the nozzle around its longitudinal axis, and the density field is reconstructed using the convolution back-projection (CBP) method. The three-dimensional density field of the elliptic jet is acquired with a nominal spatial resolution of approximately 13 <span>(upmu)</span>m. The flow characteristics of shock-containing elliptic jets, such as the shock-cell length, the supersonic length, the switchover location, and the axis-switching location, are quantitatively revealed from the streamwise density profiles, the density contour plots in the minor-axis and major-axis planes where a method is proposed to quantitatively estimate the switchover and axis-switching locations. The shock-cell and supersonic lengths are quantitatively compared with the recently introduced analytical solution and scaling law, respectively. In addition, the shock structures and topology showing the spatial evolution in the streamwise direction of the near-field shock system within the elliptic jet are experimentally demonstrated for the first time.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamics of impact of polymer droplets on viscoelastic surfaces 聚合物液滴对粘弹性表面的动态影响

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-24 DOI: 10.1007/s00348-024-03886-x

Saurabh Yadav, Binita Pathak

引用次数: 0

Characterization of a hypersonic turbulent boundary layer along a sharp cone with smooth and transverse square−bar roughened wall 带有光滑和横向方棒粗化壁的尖锥沿线高超音速湍流边界层的特征描述

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-18 DOI: 10.1007/s00348-024-03876-z

Dominik Neeb, Pascal Marquardt, Ali Gülhan

{"title":"Characterization of a hypersonic turbulent boundary layer along a sharp cone with smooth and transverse square−bar roughened wall","authors":"Dominik Neeb, Pascal Marquardt, Ali Gülhan","doi":"10.1007/s00348-024-03876-z","DOIUrl":"10.1007/s00348-024-03876-z","url":null,"abstract":"<div><p>In the present study, the response of a hypersonic turbulent boundary layer at an inflow of <i>Ma</i><sub>∞</sub> = 6 and <i>Re</i><sub>∞</sub> = 16·10<sup>6</sup> 1/m to a smooth and rough surface along a sharp cone is examined. The model consisted of three segments with exchangeable parts to consider smooth and rough surfaces with a roughness topology of square bar elements with a nominal wavelength of four times the height of the elements. In selected regions of interest, the flow field was measured by particle image velocimetry (PIV) which enabled analysis of mean velocity fields and Reynolds stresses. Van Driest transformed smooth wall mean velocity profiles showed the expected incompressible behavior and compared well to previous investigations. A combination of an integral and fitting approach is discussed to enable inner scaling of the rough wall profiles, which showed the expected shift below the smooth wall profile. The smooth wall turbulence profiles from PIV agreed to artificially filtered DNS in case of the streamwise component. Turbulence profiles above the smooth and rough wall agreed to within measurement accuracies. Additionally, two−point correlations were used to investigate turbulent structures above the smooth and rough wall. Both, length scales and orientations of the correlations, showed high level of agreement between smooth and rough walls, with only differences close to the wall. Furthermore, uniform momentum zones could be identified with similar behavior along both smooth and rough walls. Information from turbulence data support outer layer similarity, whereas mean velocity profiles show an increase in Coles wake parameter for the rough wall data. This might be influenced by transitional roughness effects.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-024-03876-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correction to: Particle image velocimetry in refractive index felds of combustion flows 更正：燃烧流折射率场中的粒子图像测速仪

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-16 DOI: 10.1007/s00348-024-03861-6

Christoph Vanselow, Dirk Stöbener, Johannes Kiefer, Andreas Fischer

引用次数: 0

A meshless and binless approach to compute statistics in 3D ensemble PTV 计算三维集合 PTV 统计数据的无网格和无二进制方法

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-14 DOI: 10.1007/s00348-024-03878-x

Manuel Ratz, Miguel A. Mendez

{"title":"A meshless and binless approach to compute statistics in 3D ensemble PTV","authors":"Manuel Ratz, Miguel A. Mendez","doi":"10.1007/s00348-024-03878-x","DOIUrl":"10.1007/s00348-024-03878-x","url":null,"abstract":"<div><p>We propose a method to obtain super-resolution of turbulent statistics for three-dimensional ensemble particle tracking velocimetry (EPTV). The method is “meshless” because it does not require the definition of a grid for computing derivatives, and it is “binless” because it does not require the definition of bins to compute local statistics. The method combines the constrained radial basis function (RBF) formalism introduced Sperotto et al. (Meas Sci Technol 33:094005, 2022) with an ensemble trick for the RBF regression of flow statistics. The computational cost for the RBF regression is alleviated using the partition of unity method (PUM). Three test cases are considered: (1) a 1D illustrative problem on a Gaussian process, (2) a 3D synthetic test case reproducing a 3D jet-like flow, and (3) an experimental dataset collected for an underwater jet flow at <span>(text {Re} = 6750)</span> using a four-camera 3D PTV system. For each test case, the method performances are compared to traditional binning approaches such as Gaussian weighting (Agüí and Jiménez in JFM 185:447–468, 1987), local polynomial fitting (Agüera et al. in Meas Sci Technol 27:124011, 2016), as well as binned versions of RBFs.\u0000</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142253492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

KF-PEV: a causal Kalman filter-based particle event velocimetry KF-PEV：基于因果卡尔曼滤波器的粒子事件测速仪

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-11 DOI: 10.1007/s00348-024-03877-y

Osama AlSattam, Michael Mongin, Mitchell Grose, Sidaard Gunasekaran, Keigo Hirakawa

{"title":"KF-PEV: a causal Kalman filter-based particle event velocimetry","authors":"Osama AlSattam, Michael Mongin, Mitchell Grose, Sidaard Gunasekaran, Keigo Hirakawa","doi":"10.1007/s00348-024-03877-y","DOIUrl":"10.1007/s00348-024-03877-y","url":null,"abstract":"<div><p>Event-based pixel sensors asynchronously report changes in log-intensity in microsecond-order resolution. Its exceptional speed, cost effectiveness, and sparse event stream make it an attractive imaging modality for particle tracking velocimetry. In this work, we propose a causal Kalman filter-based particle event velocimetry (KF-PEV). Using the Kalman filter model to track the events generated by the particles seeded in the flow medium, KF-PEV yields the linear least squares estimate of the particle track velocities corresponding to the flow vector field. KF-PEV processes events in a computationally efficient and streaming manner (i.e., causal and iteratively updating). Our simulation-based benchmarking study with synthetic particle event data confirms that the proposed KF-PEV outperforms the conventional frame-based particle image/tracking velocimetry as well as the state-of-the-art event-based particle velocimetry methods. In a real-world water tunnel event-based sensor data experiment performed on what we believe to be the widest field view ever reported, KF-PEV accurately predicted the expected flow field of the SD7003 wing, including details such as the lower velocity in the wake and the flow separation around the underside of an angled wing.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-024-03877-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multiphase distribution in partly saturated hierarchical nonwoven fibre networks under applied load using X-ray computed tomography 利用 X 射线计算机断层扫描分析外加载荷作用下部分饱和分层无纺纤维网中的多相分布

IF 2.3 3区工程技术

Experiments in Fluids Pub Date : 2024-09-09 DOI: 10.1007/s00348-024-03869-y

Patrick Wegele, Tomas Rosén, Daniel Söderberg

{"title":"Multiphase distribution in partly saturated hierarchical nonwoven fibre networks under applied load using X-ray computed tomography","authors":"Patrick Wegele, Tomas Rosén, Daniel Söderberg","doi":"10.1007/s00348-024-03869-y","DOIUrl":"10.1007/s00348-024-03869-y","url":null,"abstract":"<div><p>In many industrial applications, nonwoven fibre networks are facilitated to operate under partly saturated conditions, allowing for filtration, liquid absorption and liquid transport. Resolving the governing liquid distribution in loaded polyamide-6 (PA6) fibre networks using X-ray computed micro-tomography is a challenge due to the similar X-ray attenuation coefficients of water and PA6 and limitations in using background subtraction techniques if the network is deformed, which will be the case if subjected to compression. In this work, we developed a method using a potassium iodide solution in water to enhance the liquid’s attenuation coefficient without modifying the water’s rheological properties. Therefore, we studied the evolving liquid distribution in loaded and partly saturated PA6 fibre networks on the microscale. Increasing the external load applied to the network, we observed an exponential decrease in air content while the liquid content was constant, increasing the overall saturation with increasing network strain. Furthermore, the microstructural properties created by the punch-needle process in the manufacturing of the network significantly influenced the out-of-plane liquid distribution. The method has been proven helpful in understanding the results of adaptions in both the fibre network design and manufacturing process, allowing for investigating the resulting liquid distribution on a microscale.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00348-024-03869-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0