Haitao Xu

Study of magnetic properties of ZnO nanoparticles codoped with Co and Cu (2009)

Xu, Haitao, Zhao, Qidong, Yang, Hua, Chen, Yan

Here, we report on systematic studies of the magnetic properties of Co and Cu codoped ZnO nanoparticles prepared by sol–gel technique. The effect of hydrogenation and shape on the magnetic...

Bulk turbulence in dilute polymer solutions (2009)

Ouellette, Nicholas T., Xu, Haitao, Bodenschatz, Eberhard

By tracking small particles in the bulk of an intensely turbulent laboratory flow, we study the effect of long-chain polymers on the Eulerian structure functions. We find that the structure functions...

Fluid Acceleration in the Bulk Turbulence of Dilute Polymer Solutions (2008)

Crawford, Alice M., Mordant, Nicolas, Xu, Haitao, Bodenschatz, Eberhard

We report experimental measurements of Lagrangian accelerations in the bulk of intense turbulent flows of dilute polymer solutions by following tracer particles with a high-speed optical tracking...

Evolution of geometric structures in intense turbulence (2008)

Xu, Haitao, Ouellette, Nicholas T., Bodenschatz, Eberhard

Abstract: We report measurements of the evolution of lines, planes and volumes in an intensely turbulent laboratory flow using high-speed particle tracking. We find that the classical characteristic...

Evolution of Geometric Structures in Intense Turbulence (2008)

Xu, Haitao, Ouellette, Nicholas T., Bodenschatz, Eberhard

We report measurements of the evolution of lines, planes and volumes in an intensely turbulent laboratory flow using high-speed particle tracking. We find that the classical characteristic timescale...

Fluid acceleration in the bulk of turbulent dilute polymer solutions (2008)

Crawford, Alice M., Mordant, Nicolas, Xu, Haitao, Bodenschatz, Eberhard

We studied the effects of long-chain polymers on the small scales of turbulence by experimental measurements of Lagrangian accelerations in the bulk of turbulent flows of dilute polymer solutions....

Tracking Lagrangian trajectories in position–velocity space (2008)

Xu, Haitao

Lagrangian particle-tracking algorithms are susceptible to intermittent loss of particle images on the sensors. The measured trajectories are often interrupted into short segments and the long-time...

Experimental measurement of acceleration correlations and pressure structure functions in high Reynolds number turbulence (2007)

Xu, Haitao, Ouellette, Nicholas T., Vincenzi, Dario, Bodenschatz, Eberhard

We present measurements of fluid particle accelerations in turbulent water flows between counter-rotating disks using three-dimensional Lagrangian particle tracking. By simultaneously following...

Modification of the turbulent energy cascade by polymer additives (2007)

Ouellette, Nicholas T., Xu, Haitao, Bodenschatz, Eberhard

By tracking small particles in the bulk of an intensely turbulent flow, we show that even a very small concentration of long-chain polymers disrupts the usual turbulent energy cascade. The polymers...

Evolution of geometric structures in intense turbulence (2007)

Xu, Haitao, Ouellette, Nicholas T., Bodenschatz, Eberhard

We report measurements of the evolution of lines, planes, and volumes in an intensely turbulent laboratory flow using high-speed particle tracking. We find that the classical characteristic time...

Suivi Lagrangien 3D de particules à haute résolution spatiale et temporelle en écoulement pleinement turbulent (2007)

BOURGOIN , Mickael, Nicholas Ouellette, Haitao Xu, Eberhard Bodenschatz

Nous présentons un dispositif permettant le suivi Lagrangien optique 3D de particules, avec une grande résolution spatio-temporelle, pour l'étude d'écoulements pleinement turbulents. Le...

Acceleration Correlations and Pressure Structure Functions in High-Reynolds Number Turbulence (2007)

Xu, Haitao, Ouellette, Nicholas T., Vincenzi, Dario, Bodenschatz, Eberhard

We present measurements of fluid particle accelerations in turbulent water flow between counterrotating disks using three-dimensional Lagrangian particle tracking. By simultaneously following...

Curvature of Lagrangian Trajectories in Turbulence (2007)

Xu, Haitao, Ouellette, Nicholas T., Bodenschatz, Eberhard

We report measurements of the curvature of Lagrangian trajectories in an intensely turbulent laboratory water flow measured with a high-speed particle-tracking system. The probability density...

A quantitative study of three-dimensional Lagrangian particle tracking algorithms (2006)

Ouellette, Nicholas T., Xu, Haitao, Bodenschatz, Eberhard

A neural network particle finding algorithm and a new four-frame predictive tracking algorithm are proposed for three-dimensional Lagrangian particle tracking (LPT). A quantitative comparison of...

High Order Lagrangian Velocity Statistics in Turbulence (2006)

Xu, Haitao, Bourgoin, Mickaël, Ouellette, Nicholas T., Bodenschatz, Eberhard

We report measurements of the Lagrangian velocity structure functions of orders 1 through 10 in a high Reynolds number (Taylor microscale Reynolds numbers of up to R(lambda) = 815 ) turbulence...

Multifractal Dimension of Lagrangian Turbulence (2006)

Xu, Haitao, Ouellette, Nicholas T., Bodenschatz, Eberhard

We report experimental measurements of the Lagrangian multifractal dimension spectrum in an intensely turbulent laboratory water flow by the optical tracking of tracer particles. The Legendre...

The Role of Pair Dispersion in Turbulent Flow (2006)

Bourgoin, Mickael, Ouellette, Nicholas T., Xu, Haitao, Berg, Jacob, Bodenschatz, Eberhard

Mixing and transport in turbulent flows—which have strong local concentration fluctuations—are essential in many natural and industrial systems including reactions in chemical mixers, combustion...

Small-scale anisotropy in Lagrangian turbulence (2006)

Ouellette, Nicholas T., Xu, Haitao, Bourgoin, Mickael, Bodenschatz, Eberhard

We report measurements of the second-order Lagrangian structure function and the Lagrangian velocity spectrum in an intensely turbulent laboratory flow. We find that the asymmetries of the...

An experimental study of turbulent relative dispersion models (2006)

Ouellette, Nicholas T., Xu, Haitao, Bourgoin, Mickael, Bodenschatz, Eberhard

We report measurements of the spreading rate of pairs of tracer particles in an intensely turbulent laboratory water flow. We compare our measurements of this turbulent relative dispersion with the...

An experimental study of turbulent relative dispersion models (2006)

Ouellette, Nicholas T., Xu, Haitao, Bourgoin, Mickaël, Bodenschatz, Eberhard

Abstract. We report measurements of the spreading rate of pairs of tracer particles in an intensely turbulent laboratory water flow. We compare our measurements of this turbulent relative dispersion...

Pair Dispersion in Turbulence (2005)

Bourgoin, Mickael, Ouellette, Nicholas T., Xu, Haitao, Joergensen, Jacob B., Bodenschatz, Eberhard

Turbulent mixing of liquids and gasses is ubiquitous in nature. It is the basis of all industrial fluid mixing processes, and it determines the spread of pollutants or bioagents in the atmosphere and...