Relative Amplitude Research Articles

A Preliminary Evaluation of Potential Perceptual Contributions from the Skull

ABSTRACT An experiment was conducted to test the common assumption that amplification produced by the outer and middle ear for air-conducted (AC) signals renders the perceptual contributions from bone conduction (BC) through the skull negligible under typical, free-field listening conditions. To evaluate this possibility, simulated BC signals reflecting varying levels of attenuation were mixed with the original version of the signal (i.e., in place of the AC signal). To simulate the BC signals, a sawtooth wave (F 0 = 43.06 Hz; maximum frequency = 5,000 Hz) was filtered using existing measurements from individual skulls as a bank of third-octave bands. The resulting signals were mixed with the original sawtooth, such that the relative peak amplitude of BC signals was −8, −20, −32, or −44 dB to the original signal. Listeners completed a 4IAX discrimination task to determine if they could detect the presence of the simulated BC signals (X) relative to the original sawtooth in isolation (A). Discrimination sensitivity (d´) tended to remain high at −8 dB and −20 dB conditions, and, as hypothesized, decreased with greater attenuation. However, d´ remained reliable (>1) for more than a quarter of the skulls, even in the −44 dB attenuation condition. This was despite the fact that third-octave bands below 3,150 Hz exceeded the combination of the expected levels of gain that are observed from AC and the measured attenuation from BC. Furthermore, remaining bands at or above 3,150 Hz reflected similar intensities for BC signals regardless of whether or not they were discriminated in the −44 dB condition. Taken together, these findings raise the possibility that at least a subset of human skulls might make audible contributions under typical (free-field) listening conditions, and certainly when the AC signal is reduced (such as when the ears are covered).

Anomalous Long-Ranged Influence of an Inclusion in Momentum-Conserving Active Fluids

We show that an inclusion placed inside a dilute Stokesian suspension of microswimmers induces power-law number-density modulations and flows. These take a different form depending on whether the inclusion is held fixed by an external force—for example, an optical tweezer—or if it is free. When the inclusion is held in place, the far-field fluid flow is a Stokeslet, while the microswimmer density decays as 1/r2+ε, with r the distance from the inclusion and ε an anomalous exponent which depends on the symmetry of the inclusion and varies continuously as a function of a dimensionless number characterizing the relative amplitudes of the convective and diffusive effects. The angular dependence takes a nontrivial form which depends on the same dimensionless number. When the inclusion is free to move, the far-field fluid flow is a stresslet, and the microswimmer density decays as 1/r2 with a simple angular dependence. These long-range modulations mediate long-range interactions between inclusions that we characterize. Published by the American Physical Society 2024

Strain mode measurement of asphalt pavements using distributed fibre optic sensor data

This paper proposes a method for measuring strain modes in asphalt pavements using distributed fibre optic strain sensor data. A processing algorithm based on cross power spectral density (CPSD) was developed to utilize high spatial resolution strain data to determine the CPSD peak frequency and corresponding relative amplitude. The proposed method was applied in both laboratory and field settings, comparing the results of distributed fibre optic cables with those of accelerometers or theoretical solutions to validate accuracy. Local heating of asphalt structures was used to test the sensitivity of the measured strain modes to changes in material properties. The results demonstrate that different fibre optic cables can provide peak frequencies comparable to traditional accelerometers (±0.6 Hz). Additionally, they offer relative amplitude with a resolution of 1 cm, achieving a modal assurance criterion exceeding 0.95 when compared to theoretical strain mode shapes. The method also sensitively reflects material property changes at different positions within the asphalt structure. This indicates that the proposed approach can effectively measure strain modes in asphalt structures, offering a more detailed understanding of the distribution of structural properties compared to traditional methods.

Identification of flow patterns in an opaque condenser tube by distributed fiber Bragg gratings

Two-phase loops with phase change heat transfer are pivotal for cooling electronics under high heat flux and for thermal control in spacecraft. Numerous studies aim to clarify the mechanisms behind these loops to enhance cooling capacity and stability, which are closely tied to flow patterns. However, conventional flow pattern identification methods, requiring transparent tubes for direct observation, are impractical for simultaneous heat transfer measurement, especially during condensation. This paper introduces a novel approach for identifying flow patterns within an opaque, vertical condensation tube using embedded distributed fiber Bragg gratings (DFBGs) for R134a. The method involves a “fingerprint” derived from temperature profile derivatives and additional criteria based on temperature variation characteristics. These include the relative deviation from saturation temperature, the relative spatial temperature gradients, and the relative amplitude of temperature fluctuations. Validation against high-speed camera images confirms the method’s efficacy. It enables the determination of flow pattern lengths, the endpoint of condensation, and the construction of a flow regime map. Additionally, it allows for the measurement of vapor velocity in slug flow, facilitating the calculation of slip ratio and void fraction, which correlates reasonably with the Zuber-Findlay model, with systematic positive deviations up to 30%. This method also paves the way for simultaneous measurement of in-tube condensation heat transfer characteristics for various flow patterns.

Dynamic phase transition region in electrically injected PT-symmetric lasers

Research on parity-time (PT) symmetry and exceptional points in non-Hermitian laser systems has been extensively conducted. However, in practical electrically injected PT-symmetric lasers, the frequency detuning and linewidth enhancement factor of the laser can influence the symmetry breaking of the system in another dimension. We find that the previous exceptional point now transforms into a dynamic phase transition region, where the states are temporally unstable, indicating the occurrence of multimode oscillation. The relative phase and field amplitude ratio in this region also exhibit many novel phenomena indicating its instability. This region can be manipulated by adjusting the coupling strength between adjacent waveguides and the pumping intensity in the loss waveguide. Experimentally, we characterize the near-field, far-field, and spectrum of several structures, and the results validate our theoretical model. This work elucidates the dynamic process and phase transition process of electrically injected PT-symmetric lasers, providing support for the practical application of PT-symmetric lasers.

Characteristic of temporal light modulation reference meter and standard light source for calibration and verification

Abstract The measurement of the temporal light modulation (TLM) of a light source is gaining increasing importance owing to its detrimental effects on human vision and health. To establish traceability in TLM measurements, the National Institute of Metrology, China (NIM), established a TLM reference meter (TLMM) and standard TLM light source (STLS) for calibration and verification services. The TLMM and STLS employ detector- and source-based approaches, respectively, to define the standards for TLM quantities. The TLMM rapidly acquires light waveform data from the TLM light sources and calculates corresponding TLM quantities. Frequency calibration result is with an expanded uncertainty of 1 × 10−5, frequency response function is almost flat in range of 1 kHz–25 kHz, and response time is less than 8 × 10−6 s. The electrical noise was evaluated at approximately 1000:1–5000:1. The STLS generates an arbitrary TLM waveform by converting the virtual waveform into an actual LED output light waveform. For the frequency response function, the relative amplitude decreased by 1% with a frequency of 15 kHz, and response time was less than 5 × 10−6 s. The linearity of the frequency dependency was studied with ratio varied by approximately 0.19% when the periodic triangle excitation in frequency band from 1 Hz to 1 kHz. Experimental comparisons demonstrated that TLM quantities (frequency, percentage flicker, flicker index, short-term flicker severity P st LM , and stroboscopic effect visibility measure ( SVM )) are consistent between the TLMM and STLS devices on 14 typical TLM waveforms. For P st LM , most of the deviations were in the range of −0.019–0.079 (except for one with 0.182). For SVM , most of the deviations were in the range of −0.001–0.003 (except for one with 0.014).

Expressions of the solenovian early oligocene crisis on the northern shelf of the Eastern Paratethys

The results of regional structure studies of the Solenovian deposits of the Eastern Paratethys Early Oligocene Rupelian Stage are presented. The geological structure and paleogeographic conditions that existed in the basin during the Solenovian time were refined on the base of complex interpretation of geological and geophysical materials. A spatial picture of the Eastern Paratethys sea level drops consequences during a series of regressions in the Oligocene period is traced. Shelf areas were periodically drained, which is reflected in the erosional unconformities structure and buried river incisions. It has been established that the most significant was the regression of the Late Solenovian time with a relative sea level drop amplitude of more than 500 m. As a result, a pronounced unconformity surface complicated by river cuts was formed inside the shelf part of the Maikop seismic complex. Erosion ledges and landslide bodies formed on the slopes, and basin-fill complexes accumulated in depression parts.

Strong turbulence and magnetic coherent structures in the interstellar medium

Magnetic turbulence is classified as weak or strong based on the relative amplitude of the magnetic field fluctuations compared to the mean field. These two classes have different energy transport properties. The purpose of this study is to analyze turbulence in the interstellar medium (ISM) based on this classification. Specifically, we examined the ISM of simulated galaxies to detect evidence of strong magnetic turbulence and provide statistics on the associated magnetic coherent structures (MCoSs), such as current sheets, that arise in this context. We analyzed magnetohydrodynamic galaxy simulations with different initial magnetic field structures (either completely ordered or completely random) and recorded statistics on the magnetic field fluctuations ($ B/B_0$) and the MCoSs, which are defined here as regions where the current density surpasses a certain threshold. We also studied the MCoS sizes and kinematics. The magnetic field disturbances in both models follow a log-normal distribution, peaking at values close to unity; this distribution turns into a power law at large values ($ B/B_0 > 1$), which is consistent with strong magnetic turbulence The current densities are widely distributed, with non-power-law deviations from a log-normal at the largest values. These deviating values of the current density define MCoSs. We find that, in both models, MCoSs are fractally distributed in space, with a typical volume-filling factor of about 10 percent, and tend to coincide with peaks of star formation density. Their fractal dimension is close to unity on sub-kiloparsec scales, and between 2 and 3 on larger scales. These values are consistent with MCoSs having a sheet-like or filament-like morphology. Our work challenges the prevailing paradigm of weak magnetic turbulence in the ISM by demonstrating that strong magnetic disturbances can occur even when the initial magnetic field is completely ordered. This strong magnetic turbulence arises self-consistently from differential rotation and supernova feedback. Our findings provide a foundation for a magnetic turbulence description of the galactic ISM that includes strong fluctuations of the magnetic field.

Numerical and Experimental Power Output Estimation for a Small-Scale Hinged Wave Energy Converter

Wave energy converters (WECs) integrated into breakwaters present a promising solution for combining coastal protection with renewable energy generation, addressing both energy demands and environmental concerns. Additionally, this integration offers cost-sharing opportunities, making the overall investment more economically viable. This study explores the potential of a hinged point-absorber WEC, specifically designed as a floating hinged half-sphere, by assessing the device’s power output and comparing two different breakwater configurations. To evaluate the device’s performance, a comprehensive numerical and experimental approach was adopted. Numerical simulations were carried out using a radiation-diffraction model, a time domain tool for analyzing wave–structure interactions. These simulations predicted average power outputs of 25 kW for sloped breakwaters and 18 kW for vertical breakwaters located at two strategic sites: the Port of Leixões and the mouth of the Douro River in Portugal. To validate these predictions, a 1:14 scale model of the WEC was constructed and subjected to testing in a wave–current flume, replicating different sea-state conditions. The experimental results closely aligned with the numerical simulations, demonstrating a good match in terms of relative error and relative amplitude operator (RAO). This alignment confirms the reliability of the predictive model. These findings support the potential of integrating WECs into breakwaters, contributing to port energy self-sufficiency and decarbonization.

Physical states and transition amplitudes in piecewise flat quantum gravity

In this paper, we show how the path integral for gravity and matter on a piecewise flat spacetime can be used to define the physical quantum gravity states and the related transition amplitudes. The physical states are given by the path integrals for open manifolds from a certain topological class, while the corresponding transition amplitudes are obtained by gluing two such open manifolds into a closed one and calculating the corresponding path integral. We also solve the problem of how to associate a quantum gravity state to an effective action. This is done by using the path integral for a closed manifold from the transition-amplitude topological class so that the state which corresponds to the effective action can be chosen to be the Hartle–Hawking or the Vilenkin wavefunction for the vacuum manifold component of the transition-amplitude manifold.

The development of a bio-inspired vibration source localization algorithm

Vibration source localization is an interdisciplinary topic that has applications in both engineering and biology. To develop bio-inspired technologies that can be applied in engineering, a vibration source localization algorithm is developed based on a spider dynamic model. The model includes: (i) a point source; (ii) a spider model with 8 legs resting on a non-dispersive substrate that introduces correlated leg inputs. The proposed algorithm first calculates the leg inputs using a backward filter forward smoother algorithm with given leg responses to the excitation from the vibration source; and then estimates the source angle, source distance, wave speed and decay rate through optimization. The optimization utilizes the time and amplitude relationships between the leg inputs and the leg-substrate contact locations. The effectiveness of the algorithm is validated by comparing the algorithm estimations with the actual parameters. Results show that the algorithm gives accurate estimation of the source angle and wave speed usually with errors within 3 deg and 1 m/s, respectively, but cannot estimate the source distance. Two spatially-separated spider-like models are needed for estimating the source distance. The algorithm works well even under low signal-to-noise ratio down to 11 dB.

ZTF SN Ia DR2: Impact of the galaxy cluster environment on the stretch distribution of Type Ia supernovae

Understanding the impact of the astrophysical environment on Type Ia supernova (SN Ia) properties is crucial to minimize systematic uncertainties in cosmological analyses based on this probe. We investigate the dependence of the SN Ia SALT2.4 light-curve stretch on the distance from their nearest galaxy cluster to study the potential effect of the intracluster medium (ICM) environment on the intrinsic properties of SN Ia. We used the largest SN Ia sample to date and cross-matched it with existing X-ray, Sunyaev-Zel'dovich, and optical cluster catalogs in order to study the relation between the stretch and the distance to the nearest detected cluster from each SN Ia. We modeled the underlying stretch distribution with a Gaussian mixture with relative amplitudes that depended on redshift and clustercentric distance. We find that the fit quality of the stretch distribution improves significantly when we included the distance-dependant term in the model with a variation of the Akaike information criterion $ AIC = -10.2$. Because of the known correlation between galaxy age and distance from the cluster center, this supports previous evidence that the age of the stellar population is the underlying driver of the bimodal shape of the SN Ia stretch distribution. We further computed the evolution of the fraction of quenched galaxies as a function of distance with respect to cluster center from our best-fit model of the SNe Ia stretch distribution and compared it to previous results obtained from $H line measurements, optical broadband photometry, and simulations. We find our estimate to be compatible with these results. The results of this work indicate that SNe Ia searches at high redshift targeted toward clusters to maximize detection probability should be considered with caution as the stretch distribution of the detected sample would be strongly biased toward the old subpopulation of SNe Ia. Furthermore, the effect of the ICM environment on the SN Ia properties appears to be significant from the center of the clusters up to their splashback radius. This is compatible with previous works based on observations and simulations of a galaxy age gradient with respect to clustercentric distance in massive cluster halos. The next generation of large-area surveys will provide an increase of an order of magnitude in the size of SN Ia and cluster catalogs. This will enable us to analyze the impact of cluster mass on the intrinsic properties of SNe Ia and of the fraction of quenched galaxies in the outskirts of clusters in more detail, where direct measurements are challenging.

Associations between rest–activity/light-exposure rhythm characteristics and depression in United States adults: A population-based study

This cross-sectional study investigated the association between 24-hour rest-activity rhythm (RAR), light exposure rhythm (LER), and depression symptoms in American adults, using data from the National Health and Nutrition Examination Survey (2011–2014, N = 6852). RAR and LER characteristics were derived from a 24-hour activity recorder and analyzed using the extended cosine model, focusing on intradaily variability (IV), interdaily stability (IS), and relative amplitude (RA). Depression was assessed via the Patient Health Questionnaire-9 (PHQ-9).Multiple logistic and linear regression models showed that higher IV in RAR and LER were associated with increased depression risk (RAR-IV OR = 1.92 [95 % CI: 0.89–4.13]; LER-IV OR = 2.5 [1.45–4.30]), while higher IS and RA in both rhythms were linked to lower depression risk (RAR-IS OR = 0.22 [0.10–0.48], RAR-RA OR = 0.20 [0.11–0.37], LER-IS OR = 0.22 [0.10–0.49], LER-RA OR = 0.29 [0.15–0.56]). Participants in the highest tertile for IS and RA had a significantly lower depression risk compared to the lowest tertile. Subgroup analyses indicated interactions between age and RAR-IV, gender and LER-IV, and BMI and LER-RA (p-interaction < 0.05). Disruptions in RAR and LER are positively associated with depression, emphasizing the need for rhythm regulation interventions considering age, gender, and BMI factors.

Solar Activity Dependence of Traveling Ionospheric Disturbance Amplitudes Using a Rapid‐Run Ionosonde in High Latitudes

AbstractWe investigated the amplitude of medium scale traveling ionospheric disturbances (MSTIDs, with periods 25–100 min) and their dependence on the solar activity using 16 years data of the rapid run‐ionosonde operating at high latitudes (N, Sodankylä, Finland). A deep learning neural network was applied to ionograms to extract critical frequency of the F2 region (foF2) with a 1 min time resolution. Then, we analyzed the relative amplitude of MSTIDs (i.e., foF2/foF2), which corresponds to the amplitude of atmospheric gravity waves (AGWs) causing MSTIDs. The amplitude of AGWs propagating upward increases with height due to the decreasing density of the air, and hmF2 varies depending on local time, seasonal and solar activity conditions. To account for this effect, we calculated a corrected MSTID amplitude by normalizing the relative amplitude for the air density at the hmF2. The corrected amplitudes show no clear dependence on F10.7 during winter (0–12 UT), equinox (20‐01 UT) and summer (19‐01 UT), while a positive dependence of corrected amplitudes on F10.7 was observed during winter and equinox, in 14–22 UT and 15–19 UT, respectively. Corresponding to the dependence behaviors of corrected and relative amplitudes, two likely mechanisms of MSTIDs, AGWs from the lower atmosphere and auroral sources, are inferred. Their subsequent roles in the solar activity dependence of MSTID amplitudes were separately discussed, although in reality, the observed dependence is complex and often involves several mechanisms together.

Seasonal Variation of the Martian Dayside Ionosphere

AbstractThe Martian ionosphere has many similarities and differences compared to Earth, attracting significant attention. This paper utilizes radio occultation data from the Mars Global Surveyor (MGS), Mars Atmosphere and Volatile Evolution Mission (MAVEN), and ESA Mars Express mission (MEX), associated with the measurements from Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) aboard MEX, to investigate the seasonal variation of the Martian dayside ionosphere. Data preprocessing is performed first to isolate the influence of solar zenith angle and solar radiation, the seasonal variation of the Martian dayside ionosphere explored in this study. The results suggest that the peak electron density reaches its minimum and maximum at LS = 70.2° and LS = 250.2°, respectively, with an amplitude of 16.5% concerning the average (LS is referred to as the solar longitude of Mars). The peak altitude experiences its minimum at LS = 78.4° and maximum at LS = 258.4°, and its relative amplitude is 12.1%. The outcomes suggest that the seasonal variations in the Martian ionosphere are primarily attributed to the Mars‐Sun distance change, which is different from the situation on Earth. This study will benefit both Martian ionosphere modeling and Earth’s ionosphere understanding in the future.

Peridynamics model of torsion-warping: Application to lattice beam structures

This paper presents a finite deformation beam model based on Simo-Reissner theory in peridynamics (PD) framework to deal with torsion induced warping deformation. Seven degrees of freedom, viz. three translational, three rotational, and one warping amplitude are considered at each material point. The governing equations of the beam are obtained by employing global balance of linear and angular momenta in conjunction with Simo's assumption on the deformation field. The relation between PD resultant force, moment, bi-moment, and bi-shear states with their classical counterparts is established using the constitutive correspondence method. Numerical implementation strategy is furnished for both quasi-static and dynamic cases. The solution for quasi-static load is obtained through the Newton-Raphson method. The proposed model is validated against finite element solutions considering cantilever beam and lattice structures. Quasi-static deformation responses of 3×3×3 octet and single unit compression-torsion lattice structures are presented further to demonstrate the effectiveness of proposed beam model. A new bond breaking criterion is proposed based on critical stretch, critical relative rotation, and critical relative warping amplitude and failure of the compression-torsion lattice structures under compressive load is simulated. The Newmark-beta method is utilized to solve the governing equations for dynamic loading. Numerical simulations include dynamic analysis of octet and compression-torsion lattice structures.

Measuring the Pupillary Light Reflex Using Portable Instruments in Applied Settings.

The early components of the pupillary light reflex (PLR) are governed by the parasympathetic nervous system. The use of cheap, portable pupillometry devices may allow for the testing of parasympathetic-system health in field settings. We examined the reliability of two portable instruments for measuring the PLR and their sensitivity to individual differences known to modulate the PLR. Parameters of the PLR were measured in a community sample (N = 108) in a variety of field settings. Measurements were taken using a commercial pupillometer (NeuroLight, IDMED) and an iPhone using the Reflex Pro PLR analyser (Brightlamp). The parameters of baseline pupil diameter, constriction latency, amplitude and relative amplitude of constriction, and constriction velocity were measured. Individual differences related to age, levels of anxiety, and post-traumatic stress disorder (PTSD) symptomology were assessed. Some measures could not be attained using the iPhone under these field conditions. The reliability of the measures was high, save for the measurement of contraction latency which was particularly unreliable for the iPhone system. The parameters of the PLR showed the same internal relationships as those established in laboratory-based measurements. Age was negatively correlated with all the reliable PLR parameters for both systems. Effects of anxiety and PTSD symptomology were also apparent. The study demonstrated that a hand-held portable infrared pupillometer can be used successfully to measure the PLR parameters under field settings and can be used to examine individual differences. This may allow these devices to be used in workplaces, sports fields, roadsides, etc., to examine parasympathetic activity where needed.

Localization of partial electrical discharges using compressive spherical frequency-difference beamforming.

Accurate localization of partial electrical discharges is essential for the diagnosis of high-voltage systems. The current study achieves this by employing an acoustic sensor array and a beamforming approach. The occurrence of a partial discharge is accompanied by the emission of high-frequency sounds in the ultrasonic range, making localization a challenging task requiring many sensors to avoid spatial aliasing. Compressive frequency-difference beamforming, as previously proposed, can be effective in addressing this issue. We expand the method to include near-field localization by utilizing a spherical wave and propose a two-step normalization process. This eliminates the bias associated with nonplanar waves and standardizes the field variables, thereby preserving only the phase and relative amplitude information. A distributed algorithm based on the alternating direction multiplier method is used to solve the associated convex optimization problem. The proposed method is demonstrated using simulated and experimental data.

Electrostatic Waves and Electron Holes in Simulations of Low-Mach Quasi-perpendicular Shocks

Collisionless low-Mach-number shocks are abundant in astrophysical and space plasma environments, exhibiting complex wave activity and wave–particle interactions. In this paper, we present 2D Particle-in-Cell (PIC) simulations of quasi-perpendicular nonrelativistic (v sh ≈ (5500–22000) km s−1) low-Mach-number shocks, with a specific focus on studying electrostatic waves in the shock ramp and precursor regions. In these shocks, an ion-scale oblique whistler wave creates a configuration with two hot counterstreaming electron beams, which drive unstable electron acoustic waves (EAWs) that can turn into electrostatic solitary waves (ESWs) at the late stage of their evolution. By conducting simulations with periodic boundaries, we show that the EAW properties agree with linear dispersion analysis. The characteristics of ESWs in shock simulations, including their wavelength and amplitude, depend on the shock velocity. When extrapolated to shocks with realistic velocities (v sh ≈ 300 km s−1), the ESW wavelength is reduced to one-tenth of the electron skin depth and the ESW amplitude is anticipated to surpass that of the quasi-static electric field by more than a factor of 100. These theoretical predictions may explain a discrepancy, between PIC and satellite measurements, in the relative amplitude of high- and low-frequency electric field fluctuations.

Morphological properties of two-dimensional and three-dimensional bedforms in open channel flow: A flume experiments study

Bedforms are formed by sediment particles under the action of flow, which in turn affect flow and sediment movement. However, the fundamental mechanisms behind the formation and development of bedforms under varying flow conditions, the interconnection between sediment particle movement and bed morphology development, as well as the influence of bedforms on flow and sediment transport, are still not well understood. In the current study, the moveable bed load transport flume experiments under different flow conditions were done, and the development processes of two-dimensional and three-dimensional dunes formed under different flow intensities were simulated. The detailed structure of the bedforms was measured by laser scanning technology, the characteristics of the bedforms were analyzed in detail, and the relations between the formation of the bedforms and the movement of sediment particles are discussed. The results found that the correlation coefficients of the longitudinal profile curve can serve as a quick reference for distinguishing two-dimensional and three-dimensional dunes. When the crestline ratio is used as the criterion for two-dimensional and three-dimensional dunes, the relative amplitude of the dune crestline and the included angle with the flow direction should also be comprehensively considered. The lee side angles of dunes calculated using the triangle generalization method and local section tangent method are compared and show that the values obtained by the former method are only about half of that of the latter. It is also found that the lee side angles of dunes are related to the dune height. The superimposed dunes generally exist in the downstream area of the stoss side of the dunes. The local bed slopes on the stoss side of the dunes show reverse slopes. The superimposed dunes improve the local bed height and further increase the reverse slope degree of the stoss side. A streamwise ridge is an important form located in the upstream area of the dunes stoss side, and they are symmetrically distributed on both sides. Multiple streamwise ridges divide the stoss side of the dunes into relatively independent movement areas, restricting the movement of sediment particles to specific regions. According to the distribution characteristics of bed morphologies, the effects of dunes on sediment particle movement and flow energy consumption are analyzed.