Spatial Velocity Distribution Research Articles

Insight into transport performance at the interface of porous catalytic particle by means of numerical simulation

The double slip effect plays an important role in transport characteristics at the permeable porous interface between porous catalytic particle and free fluid, especially for coke deposition process. In this work, a direct pore-scale simulation is carried out via lattice Boltzmann method to investigate the mass, momentum and heat transfer process inside a porous composite system. The spatial distribution of velocity and temperature under the gas rarefaction effect is analyzed. Meanwhile, the impact of coke deposition on the double slip effect is also revealed. The results reveal that a high gas rarefaction effect can weaken the velocity double slip, which are greatly influenced by pore structural parameters. The dynamic evolution of pore structure, flow and heat transfer characteristics of the porous interface during the coke deposition process is investigated. It is found that the heat flow bifurcation phenomenon is enhanced under a high gas rarefaction effect.

Precision of region of interest-based tri-exponential intravoxel incoherent motion quantification and the role of the Intervoxel spatial distribution of flow velocities.

The purpose of this work was to obtain precise tri-exponential intravoxel incoherent motion (IVIM) quantification in the liver using 2D (b-value and first-order motion moment [M1 ]) IVIM-DWI acquisitions and region of interest (ROI)-based fitting techniques. Diffusion MRI of the liver was performed in 10 healthy volunteers using three IVIM-DWI acquisitions: conventional monopolar, optimized monopolar, and optimized 2D (b-M1 ). For each acquisition, bi-exponential and tri-exponential full, segmented, and over-segmented ROI-based fitting and a newly proposed blood velocity SDdistribution (BVD) fitting technique were performed to obtain IVIM estimates in the right and left liver lobes. Fitting quality was evaluated using corrected Akaike information criterion. Precision metrics (test-retest repeatability, inter-reader reproducibility, and inter-lobar agreement) were evaluated using Bland-Altman analysis, repeatability/reproducibility coefficients (RPCs), and paired sample t-tests. Precision was compared across acquisitions and fitting methods. High repeatability and reproducibility was observed in the estimations of the diffusion coefficient (Dtri = [1.03 ± 0.11] × 10-3 mm2 /s; RPCs ≤ 1.34 × 10-4 mm2 /s), perfusion fractions (F1 = 3.19 ± 1.89% and F2 = 16.4± 2.07%; RPCs ≤ 2.51%), and blood velocity SDs (Vb,1 = 1.44 ± 0.14 mm/s and Vb,2 = 3.62 ± 0.13 mm/s; RPCs ≤ 0.41 mm/s) in the right liver lobe using the 2D (b-M1 ) acquisition in conjunction with BVD fitting. Using these methods, significantly larger (p< 0.01) estimates of Dtri and F1 were observed in the left lobe in comparison to the right lobe, while estimates of Vb,1 and Vb,2 demonstrated high interlobar agreement (RPCs ≤ 0.45 mm/s). The 2D (b-M1 ) IVIM-DWI data acquisition in conjunction with BVD fitting enables highly precise tri-exponential IVIM quantification in the right liver lobe.

MP-PIC investigation of glycerol steam reforming in bubbling fluidized bed for high-quality hydrogen production

A reactive multiphase particle-in-cell approach is adopted to numerically investigate the physical and thermochemical characteristics of glycerol steam reforming process in a three-dimensional bubbling fluidized bed. Via the model verification, the simulated results are in acceptable agreement with the experimental measurements. The gas-solid flow hydrodynamics and the particle thermochemical properties are explored. In addition, the effects of different operating parameters (reaction temperature, particle diameter, steam/glycerol ratio, operating pressure) on the performance of the glycerol steam reforming system are discussed. The results reveal the significantly non-uniform spatial distribution of particle temperature and heat transfer coefficient (HTC) due to the intense endothermic reactions and nonlinear hydrodynamics. Comparatively large HTC of solid particles appears in the lower part of the bed. Enlarging the reaction temperature and operating pressure give rise to a larger particle HTC. The back-mixing and internal circulation behavior of particles highly influence the spatial distribution of particle velocity inside the bed. The slip velocity of particle accumulated around the gas feeding port is obviously large. The slip velocity and HTC of particle are almost positively correlated. Decreasing the steam/glycerol ratio enhances the particle thermochemical properties. Moreover, elevating the reaction temperature significantly promotes the yields of H2 and CO while the formation of CH4 is suppressed.

Energy loss caused by the elbow of stiff shotcrete pneumatic conveying based on response surface method and CFD-DEM

To explore the energy loss caused by the elbow in the pneumatic transportation of stiff shotcrete, the numerical simulation of the gas-solid flow of stiff shotcrete was carried out based on CFD-DEM. The accuracy of the simulation results was verified by on-site test and parameter calibration. The relationship between air velocity, feed rate, R/D ratio, energy loss caused by elbow and maximum wear rate was studied by response surface methodology. A second-order response surface model between the energy loss caused by elbow and each factor was established. The relationship between the maximum wear rate and each factor was obtained. The effects of air velocity, feeding rate, and R/D ratio on the spatial position and velocity distribution of particles were revealed. This paper can provide a reference for the pneumatic conveying of shotcrete. • The effects of the solid-gas ratio on the energy loss caused by the elbow are studied. • Energy loss caused by the elbow shows a quadratic perturbation with the change of factors. • The maximum wear has a linear relationship with the factors. • The spatial and velocity distributions of particles at different positions are revealed.

Unpiloted Aerial Vehicle (UAV) image velocimetry for validation of two-dimensional hydraulic model simulations

Non-intrusive image-based techniques for measuring surface river velocities have rapidly evolved as a cost-effective and safe means for quantifying flow patterns. Large-scale particle image velocimetry (LSPIV) can provide instantaneous surface velocities over a large spatial footprint rapidly and with little pre-calibration as compared to traditional techniques. Assessment of the spatial distribution of flow velocities in hydraulic models has been comparatively harder to achieve than assessment of depth due to logistical challenges but would be aided using large observational datasets that represent the variability and distribution of flow hydraulics. Additionally, the efficacy of image velocimetry in assessing the accuracy of outputs from 2D hydraulic models has not been addressed. Here, we demonstrate how LSPIV can be used to calibrate and validate 2D model predictions in a gravel bed river reach. LSPIV velocities are depth-averaged using standard velocity coefficients (α) and then using the Probability Concept (PC) - a probabilistic formulation of velocity distributions that accounts for non-standard velocity profiles, typical in field settings. UAV surveys were used to acquire video for LSPIV and imagery for Structure from Motion (SfM) topographic modelling. We use spatially dense acoustic doppler current profiler (aDcp) velocity data for benchmark assessment of the velocity outputs of HEC-RAS 2D model simulations. 2D model prediction error, based on seeded LSPIV velocities, was within range (4.2%) of the aDcp parametrised model, with improvements in modelled versus predicted velocity correlations (up to 7.7%) when using PC to depth average LSPIV velocities. Validation bias reduced significantly (11%) with tighter error distributions when compared to the aDcp based model. Although additional hydraulic measurements are required to parametrise the Probability Concept algorithm, the performance of 2D hydraulic models calibrated/validated with LSPIV velocities is on par with traditional techniques, demonstrating the potential of this non-intrusive, low-cost approach.

Studying the Relation of the Residual Stresses in the Ballast Layer to the Elastic Wave Propagation

During track construction or ballast bed maintenance, ballast layer compaction quality plays an essential role in the following track irregularity accumulation, its lifecycle, and maintenance costs. The ballast compaction process is characterized by its compaction and the accumulation of the stressed state. The elastic wave propagation methods are an effective way for the identification of the ballast bed compaction properties. The paper presents the theoretical and experimental studies of the ballast consolidation under the vibration loading of the sleeper. The practical laboratory study is given by the 1:2.5 scaled physical model of one sleeper and the corresponding ballast layer box. The measurements of ballast pressure and deformations under the vibration loading in the ballast layer and the photogrammetric recording of the ballast flow are carried out. The measurements demonstrate the accumulation of the residual stresses under the ballast layer. Furthermore, the measurements of elastic wave time of flight (ToF) using the shakers under the sleeper and acceleration sensors under the ballast show the substantial increase of the ToF velocities after the tamping process. Moreover, the distribution of the velocities along the sleeper is spatially inhomogeneous. The numeric simulation using the discrete element method (DEM) of the tamping and the testing processes proves the inhomogeneous wave propagation effect. The modeling shows that the main reason for the wave propagation inhomogeneity is the accumulated residual stress distribution and the minor one – the compaction density. Additionally, a method for identifying wave velocity spatial distribution is developed by wave tracing the inhomogeneous medium. The procedures allow ballast identification in the zones outside the shakers.

The estimation of sea-breeze front velocity over coastal urban using Himawari-8 images: A case study in Jakarta

&lt;p&gt;&lt;em&gt;The sea breeze is a meteorological phenomenon that occurs due to the contrast temperature between land and oceans. The propagation velocity of sea breeze are influenced strongly by e.g., synoptic wind and geographical conditions. Therefore, it is important to understand the relationship between the spatial distribution of sea breeze velocity and the surface characteristic, for instance over urbanized and less-urbanized coastal areas. When the sea breeze propagates inland, a cumulus cloudline will form in the vicinity of the sea breeze front (SBF). Previous studies have successfully detected the cloudline automatically using the morphological-snake algorithm. In this paper, we estimate the SBF velocity using Himawari-8 satellite images. The proposed method segmented the cloudline data points using a clustering approach, named machine learning-based k-means++, on the level-set obtained from snake algorithm. We then estimate the SBF velocity by calculating the haversine distance of the segmented cloudline points that propagate over time. The comparison of estimated cloudline speed with SBF speed measured at two observation sites, namely KKP and BPL, reveals the root mean square errors 1.39 m/s and 1.41 m/s, respectively. And the propagation direction was mainly southward.&lt;/em&gt;&lt;/p&gt;

Three-dimensional multi-physical simulation of a reverse electrodialysis stack with profiled membranes

To effectively describe the hydrodynamic and electrochemical behaviors of a reverse electrodialysis (RED) stack with profiled membranes, a multi-physical model based on Nernst–Planck framework was developed in three dimensions. Periodic domain of a cell pair of RED stack was simulated by means of finite element method. The spatial distribution of fluid velocity, ion concentration, electrical potential and current density within the cell pair was investigated. The effects of fluid velocity, inlet solution concentration and fixed charge concentration on the performances of RED stack were explored. The simulation results suggested the advantage of wave-profiled membranes with wavy sub-corrugations in improving fluid mixing and ion transport. When the ionic conductivity of feed solutions (usually low concentration solution) is lower than that of membranes, ions tend to be transported through the wavy sub-corrugations, which shortens the ion transport path through flow channels. However, this facilitating effect gradually decreases with the concentrations of feed solutions increasing. Compared with the spacer-type and empty-type stacks, the wave-type stack has the lowest internal resistances. The present model provides an effective prediction tool for the investigation of the effects of stack features and operating parameters.

Calculation of spatial and temporal distributions of temperature and velocity of a weld pool during laser welding

The laser welding process is one of the most widely used processes in the industry. The study of the distributions of temperature and fluid velocity in the weld pool plays an important role in determining the size and shape of the weld. In this paper, we are interested in the numerical study of the welding phenomenon in the weld pool resulting from the interaction of a laser beam with a magnesium alloy (AZ91). We use the equation of energy, the equations of conservation of movement, the equation of continuity, and the equation of phase transition energy; we take into account the effect of Marangoni and buoyancy force. For the numerical model, we use the Finite Volume Method (FVM) and Gauss-Seidel iterative method. We calculate spatial and temporal distributions of temperature and fluid velocity in a cylindrical coordinates system (r, θ, z). We study how laser Power and welding speed affect the width and the depth of the weld pool. The results of this numerical model are compared with an experimental study.

Rapid velocity reduction and drift potential assessment of off-nozzle pesticide droplets

• Spatial velocities of off-nozzle droplets reduce by 50%–80% when falling 200 mm. • The diameter boundary of the droplet sensitive to the drift loss is about 150 μm. • The mechanism of velocity evolution differences between droplets is clarified. • The droplet diameter distribution is well improved by the modification of liquid. • Addition of adjuvant reduces the spatial drift loss of pesticide droplets by 20%–50%. The droplet velocity and diameter significantly affect both the spatial drift loss and the interfacial deposition behaviors, thus determining the ultimate utilization efficiency during pesticide spraying. Investigating the spatial velocity and diameter evolutions can reveal the mechanism of drift loss and guide to design regulation strategy. Here, we explored the spatial velocity distribution of droplets after leaving the nozzle by particle image velocimetry technology and particle tracking model, considering that the effect of nozzle configuration and the air velocity. It shows that all droplets decelerate rapidly with the velocity attenuation ratio ranging from 50% to 80% within the region of 200 mm below the nozzle. The spatial velocity evolution differences between droplets in crossflow are determined by the competition of vertical drag force and net gravity, and the drag force sharply increases as the droplet diameter decreases, especially for that smaller than 150 μm. Based on the spatial evolution differences of the droplet velocity and diameter, a functional adjuvant was added to the liquid for improving the diameter distribution. And the drift loss was significantly reduced due to the reduction of the proportion of easily drifting droplets.

Influence of Open-Pit Coal Mining on Ground Surface Deformation of Permafrost in the Muli Region in the Qinghai-Tibet Plateau, China

The Qinghai-Tibet Plateau (QTP) is the largest mid-to low latitude and high-altitude permafrost. Open-pit coal mining and other activities have caused serious damage to the alpine ecological environment and have accelerated the degradation of permafrost on the QTP. In this study, the influence of open-pit coal mining on the time series ground surface deformation of the permafrost in the Muli region of the QTP was analyzed from 19 January 2018 to 22 December 2020 based on Landsat, Gaofen, and Sentinel remote sensing data. The primary methods include human-computer interactive visual interpretation and the small baseline subsets interferometric synthetic aperture radar (SBAS-InSAR) method. The results showed that the spatial distribution of displacement velocity exhibits a considerably different pattern in the Muli region. Alpine meadow is the main land use/land cover (LULC) in the Muli region, and the surface displacement was mainly subsidence. The surface subsidence trend in alpine marsh meadows was obvious, with a subsidence displacement velocity of 10–30 mm/a. Under the influence of changes in temperature, the permafrost surface displacement was characteristics of regular thaw subsidence and freeze uplift. Surface deformation of the mining area is relatively severe, with maximum uplift displacement velocity of 74.31 mm/a and maximum subsidence displacement velocity of 167.51 mm/a. Open-pit coal mining had resulted in the destruction of 48.73 km2 of natural landscape in the Muli region. Mining development in the Muli region had increased the soil moisture of the alpine marsh meadow around the mining area, resulting in considerable cumulative displacement near the mining area and the acceleration of permafrost degradation.

Effect of gas-induced inlet design on flow pattern and energy loss for small-scale countercurrent vortex reactor: Numerical simulation and experimental investigation

Small-scale vortex reactors have gained attention in the fields of gas-particle multiphase reactions because of the great potential of process intensification. Their performances highly depend upon the vortex flow-induced structure. However, its role has not yet been completely understood. To address the effect of the vortex flow-induced design of a small-scale countercurrent vortex reactor, the gas-induced inlet design with varying aspect ratio (the ratio of inlet height to inlet width of 0.56, 2.25, and 5.06) was designed to numerically and experimentally investigate the flow distribution, energy loss, and process intensification. It was found that for a given flow rate (inlet velocity), and with increasing aspect ratio the maximum tangential velocity is increased whereas the decay of the vortex flow is decreased. The semi-empirical equations were further developed to characterize the spatial distribution of the gas tangential velocity. There is no significant differentiation in axial velocity, but the static pressure near the wall increases significantly. Moreover, the pressure drop of the reactor increases as the inlet aspect ratio increases. Finally, an aspect ratio of 2.25 was found to be optimum for potential multiphase mixing and mass transfer. The results may provide a positive reference for the vortex-flow-based process intensification.

2D vessel contrast dilution gradient (CDG) analysis using 1000 fps high speed angiography (HSA) for velocity distribution estimation.

Contrast dilution gradient (CDG) analysis is a technique used to extract velocimetric 2D information from digitally subtracted angiographic (DSA) acquisitions. This information may then be used by clinicians to quantitatively assess the effects of endovascular treatment on flow conditions surrounding pathologies of interest. The method assumes negligible diffusion conditions, making 1000 fps high speed angiography (HSA), in which diffusion between 1 ms frames may be neglected, a strong candidate for velocimetric analysis using CDG. Previous studies have demonstrated the success of CDG analysis in obtaining velocimetric one-dimensional data at the arterial centerline of simple vasculature. This study seeks to resolve velocity distributions across the entire vessel using 2D-CDG analysis with HSA acquisitions. HSA acquisitions for this study were obtained in vitro with a benchtop flow loop at 1000 fps using the XC-Actaeon (Direct Conversion Inc.) photon counting detector. 2D-CDG analyses were compared with computational fluid dynamics (CFD) via automatic co-registration of the results from each velocimetry method. This comparison was performed using mean absolute error between pixel values in each method (after temporal averaging). CDG velocity magnitudes were slightly under approximated relative to CFD results (mean velocity: 27 cm/s, mean absolute error: 4.3 cm/s) as a result of incomplete contrast filling. Relative 2D spatial velocity distributions in CDG analysis agreed well with CFD distributions qualitatively. CDG may be used to obtain velocity distributions in and surrounding vascular pathologies provided diffusion is negligible relative to convection in the flow, given a continuous gradient of contrast.

Simultaneous determination of particle size, velocity, and mass flow in dust-laden supersonic flows

The particle mass concentration and -mass flow rate are fundamental parameters for describing two-phase flows and are products of particle number, -size, -velocity, and -density. When investigating particle-induced heating augmentation, a detailed knowledge of these parameters is essential. In most of previous experimental studies considering particle-induced heating augmentation, only average particle mass flow rates are given, without any relation to measured particle sizes and -velocities within the flow or any indication of measurement uncertainty. In this work, particle number, individual particle sizes, and velocities were measured in a supersonic flow by means of shadowgraphy and particle tracking velocimetry (PTV). The goals are to determine measurement uncertainties, a particle velocity-size relation, and the spatial distribution of number, size, velocity, and mass flow rate across the nozzle exit. Experiments were conducted in a facility with a nozzle exit diameter of 30 mm, at Ma∞ = 2.1 and Re∞ = 8.2e7 1/m. Particles made of Al2O3 and up to 60 µm in size were used for seeding. Particle mass flow rates up to 50 kg/m2 s were achieved. It is shown that an additional correction procedure reduced common software uncertainties regarding shadowgraphy particle size determination from 14% to less than 6%. Discrepancies between calculated particle velocities and experimental data were found. In terms of spatial distribution, larger particles and a higher mass flow rate concentrate in the flow center. The determined particle mass flow rate uncertainty was up to 50% for PTV; for shadowgraphy, it was less than 17%.Graphical abstract

Numerical study on scour protection effect of monopile foundation based on disturbance structure

Monopile foundations, which account for more than 80% of offshore wind power support structures, also face the challenges posed by scouring problems. This paper proposes a bionic wave structure (BWS)to change the fluid movement pattern around the monopile based on the principle of disturbance and to actively weaken the scouring of the seabed. Then, the spatial flow velocity distribution of the wake vortices between the BWS and the unprotected monopile is compared, and the development history of the local scour depth, the scour range and the bed evolution law of different protective structures are quantified. Results show BWS has a good vortex breaking effect, making it almost impossible to form alternating shedding vortices. When 0 < X/D ≤ 3.6, the wake velocity ratio between the BWS and the monopile conforms to the free decay law bounded by exponential boundary and eventually decays to 0.8, and the relevant equation is obtained. When X/D > 3.6, the velocity ratio gradually increases to 1–1.2 linearly. Furthermore, no flow acceleration zone exists in the near-bed area below the elevation of X/D < 2.4 and Z/D < 0.5, and the maximum flow reduction is 86%. When X/D = 4.4, the reduced flow velocity in the near-bed area has largely recovered. Finally, the scour depth curves and the evolution of scouring patterns of different protective structures are studied based on large eddy simulations. With the protection of the BWS, Scour depths can be reduced by a maximum of 55.2% and siltation depths can be increased by a maximum of 56.2%.

Distribution of innervation zone and muscle fiber conduction velocity in the biceps brachii muscle

The spatial distributions of muscle innervation zone (IZ) and muscle fiber conduction velocity (CV) were examined in nine healthy young male participants. High-density surface electromyography (EMG) was collected from the biceps brachii muscle when subjects performed isometric elbow flexions at 20% to 80% of the maximal voluntary contraction (MVC). A total of 9498 samples of IZs were identified and CVs were calculated using the Radon transform. The center and width of IZ sample distribution were compared within four different force levels and six medial to lateral electrode column positions using repeated measures ANOVA and multiple comparison tests. Significant shifts of IZ center were observed in the medial columns (Columns 5, 6, and 7) compared with the lateral columns (Columns 3 and 4) (p < 0.05). Similarly, significant differences in the IZ width were found in Column 7 and 8 compared to Column 3 (p < 0.05). In contrast, muscle CV was unaffected by column position. Instead, muscle CV was faster at 40% and 80% MVC compared to 20% MVC (p < 0.05). The findings of this study add further insights into the physiological properties of the biceps brachii muscle.

Influence of flow and thermal characteristics on thermal comfort inside an automobile cabin under the effect of solar radiation

Present work describes the thermal comfort of the driver in an automobile cabin under the effect of solar radiation for different cooling jet directions. Three-dimensional transient cooling simulations of the in-cabin flow and heat interactions have been carried out using commercial solver ANSYS Fluent 18.1. The surface to surface (S2S) radiation model embedded within the solver has been employed to simulate the internal conditions of radiative heat transfer. The transient behavior of the flow inside the cabin has been brought out using Fourier spectra of velocity signals. The spatial distributions of temperature and velocity for different values of driver-side vertical guide vane angle have also been presented. The interaction between cooling jets from the air-conditioning vents with air inside the automobile cabin has been illustrated using iso-Q surfaces describing the vortex structures in the flow field. Variation of bulk average temperature with vertical guide vane angle is also reported in this study. The thermal comfort of the driver has been evaluated using Equivalent Temperature (ET) and Effective Draft Temperature (EDT) for different values of vertical guide vane angles. The ET and EDT values corresponding to different locations on the body of the driver have been compared to bring out the relative significance of draft and radiative heat transfer on the thermal comfort inside an automobile cabin. Optimal guide vane angle corresponding to enhanced mixing and thermal comfort has also been identified.

Visualization of the Electrohydrodynamic and Thermal Effects of AC-DBD Plasma Actuators of Plate- and Wire-Exposed Electrodes

The dielectric barrier discharge plasma actuator is a promising flow control device that uses surface discharge. The actuator generates an electrohydrodynamic force and Joule heating that contribute to the flow control. Thus, it is important to investigate the electrohydrodynamic and thermal effects on the air flow. To this end, the flow velocity field, density field, and surface temperature distribution induced by an alternating current dielectric barrier discharge plasma actuator were experimentally examined, adopting particle image velocimetry, the background oriented schlieren technique, and an infrared camera. These experiments were conducted for plate- and wire-exposed electrode plasma actuators to investigate the effect of the shape of the exposed electrode. It was confirmed that the topology of the discharge is different between the two types of plasma actuators. This results in a difference in the spatial distributions of the velocity and density fields between the two actuators. In particular, we clarified that there is an obvious difference in the peak position of the density and temperature distribution between the two actuators. We also confirmed that the difference in the spatial distribution of the vertical velocity makes the above difference.

Temperature distribution and pressure oscillation characteristics of di-tert-butyl peroxide overpressure relief in a confined space

Pressure relief can effectively reduce the damage caused by the thermal runaway reaction of organic peroxides in the chemical process. To further understand the overpressure relief mechanism of di- tert -butyl peroxide (DTBP), pressure vessel test system and numerical simulation method were combined to systematically analyze the dynamic relief characteristics of DTBP in a confined space. The three-dimensional spatial distribution and variation law of temperature, pressure, and airflow velocity during the relief process were also revealed. The results show that a high-speed under-expanded jet is generated when DTBP overpressure relief occurs, and low temperature and negative pressure are produced inside the vessel and near the vent. The airflow velocity first increases and then decreases during the relief process, with a maximum value of 487 m/s. Both the internal temperature and pressure show prominent damping oscillation characteristics, and the oscillation period is between 2.1 ms and 2.3 ms. The pressure oscillation curves at different positions present different peak shapes, and the closer to the vent, the smaller the pressure amplitude. The consistency between the experimental results and simulation data also verifies the reliability of the numerical model.

River Surface Analysis and Characterization Using FMCW Radar

Today’s warning systems for floods or droughts require sensor applications that provide a vast array of information. Current systems provide insight into either the water level or the river velocity. In order to obtain additional parameters for the characterization of the flow behavior in a noncontact manner, a frequency-modulated continuous-wave radar with chirp sequence is used. Since these sensors provide range and velocity information but also enable gathering of additional parameters. The presented measurements in this contribution were performed at four different rivers with a commercially available radar sensor. The results of the classical postprocessed 2-D fast Fourier transform are used as basis for an imagewise processing approach to obtain additional features for classifying the behavior of the river surface. For this purpose, the framewise enveloping velocities are depicted in a time sequence. Due to processing the detected reflection patterns in relation to time, a characteristic pattern for river flow profiles can be extracted. By reducing the information using time averaging, characteristic features for different flows can be extracted from the spatial envelope velocity distribution. In particular, the resulting insights lead to characteristic features for single flow distributions that enable novel monitoring systems with new possibilities to classify rivers using radar sensors.