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3D particle tracking velocimetry (PTV) is a key technique for analyzing turbulent flow, one of the most challenging computational problems of our century. At the core of 3D PTV is the dual-frame fluid motion estimation algorithm, which…

Computer Vision and Pattern Recognition · Computer Science 2024-10-17 Yifei Zhang , Huan-ang Gao , Zhou Jiang , Hao Zhao

Part segmentation and motion estimation are two fundamental problems for articulated object motion analysis. In this paper, we present a method to solve these two problems jointly from a sequence of observed point clouds of a single…

Computer Vision and Pattern Recognition · Computer Science 2025-08-08 Jun-Jee Chao , Qingyuan Jiang , Volkan Isler

The present thesis deals with the non-modal linear analysis of 3D perturbations in wall flows. In the first part,a solution to the Orr-Sommerfeld and Squire IVP, in the form of orthogonal functions expansion, is researched. The Galerkin…

Fluid Dynamics · Physics 2013-06-28 Federico Fraternale

We consider the problem of seismic velocity change estimation using ambient noise recordings. Motivated by [23] we study how the velocity change estimation is affected by seasonal fluctuations in the noise sources. More precisely, we…

Geophysics · Physics 2016-05-04 E. Daskalakis , C. P. Evangelidis , J. Garnier , N. S. Melis , G. Papanicolaou , C. Tsogka

Statistical properties of the scrape-off layer (SOL) plasma fluctuations are studied in ohmically heated plasmas in the Alcator C-Mod tokamak. For the first time, plasma fluctuations as well as parameters that describe the fluctuations are…

Plasma Physics · Physics 2020-11-11 R. Kube , A. Theodorsen , O. E. Garcia , D. Brunner , B. LaBombard , J. L. Terry

For the understanding of fluctuation measurements in heavy-ion collisions it is crucial to develop quantitatively reliable dynamical descriptions which take the non-perturbative nature of QCD near the phase transition into account. We…

High Energy Physics - Phenomenology · Physics 2019-02-20 M. Bluhm , Y. Jiang , M. Nahrgang , J. M. Pawlowski , F. Rennecke , N. Wink

This paper addresses the estimation of fractional delay and Doppler shifts in multipath channels that cause doubly selective fading-an essential task for integrated sensing and communication (ISAC) systems in high-mobility environments.…

Signal Processing · Electrical Eng. & Systems 2025-06-24 Yutaka Jitsumatsu , Liangchen Sun

This review summarizes the coherent structures (CS) based on two-point correlations and their applications, with a focus on the interpretation of statistic CS and their characteristics. We review studies on this topic, which have attracted…

Fluid Dynamics · Physics 2019-11-05 Jun Chen

In this paper, a rapid approximation method is introduced to estimate the sea surface velocity field based on scattered measurements. The method uses a simplified two-dimensional flow model as a surrogate model, which mimics the real…

Fluid Dynamics · Physics 2024-11-05 Karlo Jakac , Luka Lanča , Ante Sikirica , Stefan Ivić

Inhomogeneous refractive index fields lead to errors in optical flow velocity measurements. Former respective studies are mostly in quasi two-dimensional flows, and attribute the measurement errors to spatial gradients in the refractive…

Fluid Dynamics · Physics 2025-02-04 Huixin Li , Andreas Fischer , Marc Avila , Duo Xu

The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals, and finding the location of its maximum. This paper addresses the problem of the…

Astrophysics · Physics 2008-11-26 Carlos Allende Prieto

We investigate hydrodynamic fluctuations in a 2D granular fluid excited by a vibrating base and in the presence of gravity, focusing on the transverse velocity modes. Since the system is inhomogeneous, we measure fluctuations in horizontal…

Soft Condensed Matter · Physics 2015-05-28 Giulio Costantini , Andrea Puglisi

We present a novel method for estimating the circulations and positions of point vortices using trajectory data of passive particles in the presence of Gaussian noise. The method comprises two algorithms: the first one calculates the vortex…

Optimization and Control · Mathematics 2023-05-05 Gil Marques , Marco Martins Afonso , Sílvio Gama

Time delay estimation (TDE) is a well-known technique to investigate poloidal flows in fusion plasmas. The present work is an extension of the earlier works of A. Bencze and S. Zoletnik 2005 and B. T\'al et al. 2011. From the prospective of…

Plasma Physics · Physics 2013-07-01 Dávid Guszejnov , Attila Bencze , Sándor Zoletnik , Andreas-Krämer-Flecken

We present a novel framework for assimilating planar PIV experimental data using a variational approach to enhance the predictions of the Spalart-Allmaras RANS turbulence model. Our method applies three-dimensional constraints to the…

Fluid Dynamics · Physics 2026-01-27 Uttam Cadambi Padmanaban , Bharathram Ganapathisubramani , Sean Symon

We present here a new parameterization for the bulk motions of galaxies and clusters (in the linear regime) that can be measured statistically from the shape and amplitude of the two-dimensional two-point correlation function. We further…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Yong-Seon Song , Cristiano G. Sabiu , Robert C. Nichol , Christopher J. Miller

Line features are valid complements for point features in man-made environments. 3D-2D constraints provided by line features have been widely used in Visual Odometry (VO) and Structure-from-Motion (SfM) systems. However, how to accurately…

Robotics · Computer Science 2025-01-14 Zewen Xu , Yijia He , Hao Wei , Bo Xu , BinJian Xie , Yihong Wu

Novel experimental modalities acquire spatially resolved velocity measurements for steady state and transient flows which are of interest for engineering and biological applications. One of the drawbacks of such high resolution velocity…

Numerical Analysis · Mathematics 2015-12-31 H. Egger , T. Seitz , C. Tropea

We propose a strategy for optimizing a sensor trajectory in order to estimate the time dependence of a localized scalar source in turbulent channel flow. The approach leverages the view of the adjoint scalar field as the sensitivity of…

Computational Engineering, Finance, and Science · Computer Science 2022-02-21 Constantinos F. Panagiotou , Davide Cerizza , Tamer A. Zaki , Yosuke Hasegawa

We propose and validate a novel experimental technique to measure two-point statistics of turbulent flows. It consists in spreading rigid fibers in the flow and tracking their position and orientation in time and therefore been named…