Ratio Of Wave Amplitude Research Articles

Hydroelastic analysis of surface gravity wave interacting with elastic plate resting on a linear viscoelastic foundation

This article investigates the interaction between a surface gravity wave that propagates over an elastic plate based on linear viscoelastic foundation. The plate is considered to be thin and infinite and is modeled based on the Euler–Bernoulli beam theory. Static and dynamic boundary conditions are applied to the Laplace equation of the fluid domain. The dispersion relation of the wave–plate system is derived and ratio of surface wave amplitude and plate deflection is proposed. Considering dimensionless dispersion relation, two modes of propagating wave are attained. Problem is analyzed for two cases of presence and absence of viscous damping coefficient in the foundation of the elastic plate. It is shown that flexural rigidity of the submerged plate has considerable effect on wave decay and plate vibration. It is illustrated that shallowness has noticeable effect on the wave propagation frequency and a critical shallowness demarcates damped or overdamped excitation of the elastic plate based on the viscoelastic foundation. Moreover, effects of flexural rigidity of the plate, foundation stiffness coefficient, and foundation viscous coefficient on phase and group velocities of wave are discussed in the present study.

Anomalous Waves Triggered by Abrupt Depth Changes: Laboratory Experiments and Truncated KdV Statistical Mechanics

Recent laboratory experiments of Bolles et al. (Phys Rev Fluids 4(1):011801, 2019) demonstrate that an abrupt change in bottom topography can trigger anomalous statistics in randomized surface waves. Motivated by these observations, Majda et al. (Proc Natl Acad Sci 116(10):3982–3987, 2019) developed a theoretical framework, based on deterministic and statistical analysis of the truncated Korteweg-de Vries (TKdV) system that successfully captures key qualitative features of the experiments including the robust emergence of anomalous statistics and heightened skewness in the outgoing wavefield. Here, we extend these parallel experimental and modeling efforts with several new findings that have resulted from a synergetic interaction between the two. By precisely relating model parameters to physical ones, we calibrate the model inverse temperature to the specific conditions present in the experiments, thereby permitting a quantitative comparison. We find theoretically predicted distributions of surface displacement to match the experimental measurements with surprising detail. Prompted by the presence of surface slope in the TKdV Hamiltonian, we present new experimental measurements on surface slope statistics and compare them to model predictions. Analysis of some deterministic trajectories of TKdV elucidates the experimental length and time scales required for the statistical transition to a skewed state. Finally, the theory predicts a peculiar relationship between the outgoing displacement skewness and the change in slope variance, specifically how their ratio depends on the wave amplitude and depth ratio. New experimental measurements provide convincing evidence for this prediction.

A New Approach for Study the Electrohydrodynamic Oscillatory Flow Through a Porous Medium in a Heating Compliant Channel

The governing equations of an electrohydrodynamic oscillatory flow were simplified, using appropriate nondimensional quantities and the conversion relationships between fixed and moving frame coordinates. The obtained system of equations is solved analytically by using the regular perturbation method with a small wave number. In this study, modified non-dimensional quantities were used that made fluid pressure in the resulting equations dependent on both axial and vertical coordinates. The current study is more realistic and general than the previous studies in which the fluid pressure is considered functional only in the axial coordinate. A new approach enabled the author to find an analytical form of fluid pressure while previous studies have not been able to find it but have found only the pressure gradient. Analytical expressions for the stream function, electrical potential function and temperature distribution are obtained. The results show that the electrical potential function decreases by the increase of the Prandtl number, secondary wave amplitude ratio and width of the channel.

ДОСЛІДЖЕННЯ ПРОХОДЖЕННЯ УЛЬТРАЗВУКОВИХ ХВИЛЬ КРІЗЬ ДВОШАРОВИЙ МАТЕРІАЛ ІЗ СКЛАДНОЮ СТРУКТУРОЮ ПРИ КОНТРОЛІ ЙОГО ТЕХНОЛОГІЧНИХ ПАРАМЕТРІВ

Investigate the passage of ultrasonic waves through a two-layer material with a complex structure with non-contact control of its technological parameters. A non-contact ultrasonic method was used in the work to control technological parameters of materials with a complex structure, which takes into account the attenuation of ultrasonic waves. It is substantiated that the attenuation of an ultrasonic signal for a material with significant pores during its transverse sounding can be neglected compared to attenuation in a material without through pores. The results of studies of the influence of the thickness of a material with pores on the amplitude ratios of ultrasonic waves are presented. The dependences of the amplitudes of ultrasonic waves are obtained, one of which passes through a two-layer continuous material, and the other passes through a two-layer material with pores, taking into account the dependence of their attenuation on the thickness of the material. In this work, we obtained the dependences of the phase shift of ultrasonic waves, which were reflected from a two-layer material without pores, and waves reflected from a two-layer material with pores, on the total thickness of the controlled material, if we compare the phase of these waves with incident vibrations. Also obtained are the dependences of the change in wave amplitudes over time for a pulsed ultrasonic signal passing through a controlled material. It is proposed to use a pulsed ultrasonic signal for operational non-contact control of technological parameters of bilayer materials with a complex structure. The analysis showed that the obtained expressions for pulsed ultrasonic signals that can interact with porous materials can be used to create new methods and means of non-destructive non-contact control of technological parameters of materials with a complex structure. The aforementioned will make it possible to create complex integrated and universal contactless control devices for various technological parameters for composite materials with pores, which today are subjected only to destructive contact control, which does not allow operational monitoring directly at the plant.

Improvement of the parabolized stability equation to predict the linear evolution of disturbances in three-dimensional boundary layers based on ray tracing theory

A new method to predict the linear evolution of disturbances in three-dimensional inhomogeneous boundary layers is proposed, named RTPSE, in which the line-marching parabolized stability equation (PSE) is improved by applying ray tracing (RT) theory. Results show that RTPSE can accurately predict the spanwise wave number and amplitude ratio for both stationary and traveling crossflow waves, while the traditional PSE could not.

Abstract P141: A Novel GWAS Locus Influences Microvascular Response to Acute Psychological Stress

Background: Excessive peripheral microvascular constriction during acute psychological stress, measured using peripheral arterial tonometry reflects similar changes in coronary blood flow and is a predictor of adverse cardiovascular outcomes. The ratio of digital pulse wave amplitude during stress compared to rest (sPAT) is used to estimate the degree of microvascular response to stress. We sought to determine if genetic factors contribute to the degree of microvascular constriction during mental stress. Methods: A total of 642 post-MI and stable CAD subjects from two prospective cohort studies underwent mental stress testing with a standardized public speaking stressor. Digital pulse wave amplitude was continuously measured using PAT and the stress/rest PAT ratio (sPAT) of pulse wave amplitude during mental stress/baseline was calculated. Genotyping was performed using Illumina’s Multi-Ethnic Genotyping Array (MEGA) platform and imputed to the 1000 Genome reference panel. Race stratified genome-wide association studies (GWAS) of sPAT were conducted using linear regression of additive genetic mode adjusted for age, sex and population stratification in the two cohorts. A trans-ethnic meta-analysis integrated the four sets GWAS results. Results: Mean age was 63±9; 65% male, 35% Black. We identified two SNPs in linkage disequilibrium on chr4:185503564 and chr4:185491706 rs13353812 (with 35% and 28% allele frequency, respectively) that were associated with greater sPAT ratio ( P = 1.42E-08). The mean sPAT ratio during mental stress for subjects with none, one and two AT insertion alleles of SNP chr4:185503564 were 0.67, 0.76 and 0.93, respectively, an average of 12% (P < 0.001), per allele. Results were similar for G insertion alleles of SNP rs13353812. The nearest gene of the sPAT-associated locus is CASP3 which encodes caspase, an essential protein for apoptosis signaling and brain and hematopoietic stem cell development. Conclusion: We have identified a genetic basis for stress-induced vasomotion. Presence of the chr4:185503564 allele is associated with less vasoconstriction during mental stress, and thus may be protective against long term cardiovascular risk. These findings need further exploration.

Wave scattering through an orthotropic thermoelastic slab sandwiched between two isotropic elastic half-spaces

Present study deals with the scattering of a plane wave through an orthotropic thermoelastic slab sandwiched between two elastic half-spaces. Unlike the classical theory of thermoelasticity, we have employed non-classical thermoelastic theories (LS-theory and GL-theory) to analyze the scattering of plane waves. The amplitude ratios for different waves have been computed numerically for the considered generalized theories of thermoelasticity. The effect of the slab thickness on the amplitude ratios has been shown graphically. Moreover, the amplitude ratios of different waves (i.e., reflected, transmitted, forward and backward waves) are compared for different values of slab thickness under both the LS-theory and GL-theory.

A randomized controlled trial of cardiac resynchronization therapy in patients with prolonged atrioventricular interval: the REAL-CRT pilot study.

A prolonged PR interval is known to be associated with increased mortality and a higher risk of developing atrial fibrillation (AF). We tested the hypothesis that cardiac resynchronization therapy (CRT) is superior to conventional dual-chamber pacing with algorithms for right ventricular pacing avoidance (DDD-VPA) in preserving systolic and diastolic function and in preventing new-onset AF in patients with normal systolic function, indication for pacing and prolonged atrioventricular conduction (PR interval ≥220 ms). We randomly assigned 82 patients with ejection fraction >35%, indication for pacing and PR interval ≥220 ms to CRT or to DDD-VPA. On 12-month follow-up examination, the study and control arms did not differ in terms of left ventricular end-systolic volume (44 ± 17 mL vs. 47 ± 16 mL, P = 0.511) or ejection fraction (55 ± 6% vs. 57 ± 8%, P = 0.291). The E to A mitral wave amplitude ratio was higher in the CRT arm (1.3 ± 1.3 vs. 0.8 ± 0.4, P = 0.046) and the E wave deceleration time was longer (262 ± 83 ms vs. 205 ± 51 ms, P = 0.027). Left atrial volume was smaller in the CRT arm (64 ± 17 mL vs. 84 ± 25 mL, P = 0.035). Moreover, the functional class was lower in CRT patients (1.4 ± 0.6 vs. 1.8 ± 0.5, P = 0.010). During follow-up, CRT was associated with a lower risk of new-onset AF [hazard ratio = 0.37 (0.13-0.98), P = 0.046]. Cardiac resynchronization therapy proved superior to DDD-VPA in terms of better diastolic function, less left atrial enlargement and lower risk of new-onset AF, at 12 months. These data need to be confirmed in a larger trial with longer follow-up. URL: http://clinicaltrials.gov/ Identifier: NCT02150538.

Focal mechanisms of the 2017 North Korean nuclear test and its early collapse event

SUMMARYNorth Korea conducted sixth underground nuclear test on 3 September 2017. Unlike its previous tests, a rare subsequent collapse event occurred after about 8.5 min. As two types of distinctive shallow seismic events, accurate inversion of their focal mechanisms is important for event identification for CTBT. In this paper, we carry out moment tensor inversion of the nuclear test and the collapse event with gCAP using waveform data from dense regional seismic stations. And their focal mechanisms are further constrained with surface wave amplitude ratio. The results show that the surface wave amplitude ratio has further constraints for screening the waveform inversion results. The resolution of the focal mechanism inversion for the nuclear test is high, which is close to a Crack source. However, the resolution for the collapse event inversion is not so high and the source type is difficult to be accurately determined. One reason of the poor resolution for the collapse event may be due to the limited availability of high quality data, and complexity of the source process might be another factor.

Developing predictive models for analysis the heat transfer in sinusoidal wavy channels

In this work, empirical correlations were proposed to accurately estimate the heat transfer and pressure drop for water flow in sinusoidal wavy channels. The artificial intelligence techniques such as artificial neural network (ANN) and genetic algorithm (GA) were applied to develop the correlations. The experimental data related to the Nusselt number (Nu) and pressure drop (ΔP) in the wavy channels with various geometries were collected for the modeling. The independent variables are Reynolds number (Re) and main geometrical parameters including amplitude ratio (b/H), phase shift (φ), and number of waves (Nw). The results indicate that the ANN is a suitable technique to develop correlations for predicting thermal and flow characteristics in heat exchangers with wavy channels.

Performance optimiation of a cylindrical mini-channel heat sink using hybrid straight–wavy channel

The problem of high pressure drop remains a challenge in the design of heat sinks using the passive techniques of heat transfer enhancement. Wavy channels are widely used to improve the transfer of a mini-channel heat sink but with an undesirable pressure drop. A new channel design was proposed to enhance the performance of a cylindrical mini-channel heat sink (CMCHS) with a minimal possible pressure drop. The design was a straight–wavy hybrid channel, in which the channel path changes from straight at the entrance of the CMCHS to wavy. 3D computational fluid dynamics was performed to analye the fluid flow and heat transfer of the CMCHS. Simulation was conducted on the CMCHS water with a Reynolds number of less than 500. On the basis of entropy generation minimiation technique, CMCHS performance was optimied using different geometric parameters. The parameters included entrance channel length ratio and the wave amplitude ratios of the second and third sections of the channel. A test rig was manufactured to test CMCHSs for a wide range of operating conditions to validate the simulation model. Two models of CMCHS with straight and hybrid straight–wavy channels were developed on the basis of the optimum dimensions acquired from the numerical prediction. Results revealed that the overall performance of the CMCHS with a straight–wavy channel is better than that with a straight channel under the same operating conditions. The straight–wavy channel is more effective than the conventional straight channel in reducing the maximum surface temperature along the channel length of the CMCHS. The temperature uniformity along the CMCHS with a straight–wavy channel is better than that with a straight channel.

Peripheral Vasoconstriction During Mental Stress and Adverse Cardiovascular Outcomes in Patients With Coronary Artery Disease.

Excessive vasoconstriction in response to mental stress may be a potential mechanism by which acute psychological stress leads to adverse cardiac events. We investigated whether excessive digital vasoconstriction during acute mental stress predicts adverse cardiovascular outcomes among patients with coronary artery disease. Five hundred forty-nine patients with stable coronary artery disease (age 63±9, 76% male, 29% black) underwent mental stress testing with a standardized public speaking stressor and followed prospectively for cardiovascular end points. Digital pulse wave amplitude was continuously measured using peripheral artery tonometry (PAT, Itamar Inc). Stress/rest PAT ratio (sPAT) of pulse wave amplitude during mental stress/baseline was calculated and dichotomized by the median value into low and high sPAT ratio groups. Upon 3-year follow-up, Fine and Gray's subdistribution hazard ratios were used to examine the association between sPAT ratio and the composite end point of cardiovascular death, myocardial infarction, revascularization, and hospitalization for heart failure. The median sPAT ratio was 0.68 (interquartile range, 0.48-0.88), indicating 32% vasoconstriction with mental stress. Men were more likely to have low sPAT ratio than women (odds ratio, 1.79; P=0.007) while those on β-blockers were less likely to have low sPAT ratio (odds ratio, 0.52; P=0.003). After adjusting for demographic and cardiovascular risk factors, medications, and rate-pressure product change during mental stress, those with low sPAT ratio were at significantly higher risk of adverse outcomes (subdistribution hazard ratio, 1.77 [95% CI, 1.12-2.80]). Greater peripheral vasoconstriction with mental stress, denoted by a low sPAT ratio, is associated with a higher risk of adverse cardiovascular outcomes in patients with coronary artery disease.

The combined influences of heat transfer, compliant wall properties and slip conditions on the peristaltic flow through tube

In this research, the peristaltic flow with heat transfer through the two-dimensional horizontal tube of compliant wall properties with slip at boundaries is analyzed analytically. An approximated theoretical model is constructed of spring-backed flexible compliant walls pipe, chosen to move as sinusoidal wave. Perturbation solution of the governing equations is obtained with small parameter e, which means the amplitude ratio, and defined as the ratio of wave amplitude divided by tube radius. The influence of several parameters of slip conditions, wall properties and heat transfer on the dynamics of the liquid through the tube is mathematically studied, resulting in relations describing the fluid flow behavior and the induced net flow rate under the various values of flow parameters as “liquid compressibility, slip flow factor, and wave number”, heat transfer parameter like Prandtl number, and elastic wall parameters such as “wall tension, wall damping coefficient, wall stiffness, and wall rigidity”. Graphs for net flow rate under the effect of pervious parameters are plotted. Results disclose that the parameters of tube wall features, compressibility of liquid, Knudsen number for wall slip, and heat transfer in the presence of peristaltic pumping have a significant effect on net flow rate induced. This research has numerous related applications in different branches of science such as biological studies for blood flow motion in living creatures and also in industry including simulation of induced elastic waves for fluid flow through a tube.

Adaptive ultrasonic method for controlling the basis weight of knitted fabrics

Two main methods employed in designing knitted fabrics for production rely on a given surface density or on the basis weight (grams per square meter). The actual value of these parameters may differ. Normally, the actual basis weight of knitted fabrics is determined by weighing a sample of a certain width and length and subsequently performing the relevant conversion (ISO 3801:1977). This method involves a destruction or wasting of the material. A non-destructive ultrasonic method for determining the basis weight of textile materials was developed, which is based on a determination of the amplitude ratio of ultrasonic waves falling on the fabric and the waves passing through it. However, this method has limitations in determining the basis weight of textile materials with variable porosity, such as knitted fabrics. To improve the developed method, it is proposed to continue the measuring of an amplitude of the reflected wave from the fabric surface. In this case, it is possible to monitor the fabric porosity changes. If the distance and pore size of the controlled fabric have increased or decreased relative to the control sample, the amplitude and magnitude of the reflected wave (part of the reflected ultrasonic signal) changes and the ultrasonic device will be adapted to the fabric structure. Our studies have demonstrated the possibility of determining the fabric porosity by using an amplitude of the reflected ultrasonic wave from the fabric surface, which allows adaptively to determine the basis weight using an amplitude of transmitted ultrasonic wave. Further development of ultrasonic non-contact methods and relative devises is very important for production control.

A 3‐D Shear Wave Velocity Model for Myanmar Region

AbstractMyanmar is located at the eastern margin of the ongoing Indo‐Eurasian collision system, has experienced a complex tectonic history and is threatened by a high level of seismic hazard. Here we develop a crustal scale 3‐D seismic velocity model of Myanmar, which is not only critical for understanding the regional tectonic setting and its evolution but can also provide the foundation for a variety of seismological studies, including earthquake location determinations, earthquake focal mechanism inversions, and ground motion simulations. We use the newly deployed Earth Observatory of Singapore‐Myanmar broadband seismic network and other seismic stations in and around Myanmar to study the station‐based 1‐D velocity structure through a joint inversion of receiver functions, H/V amplitude ratio of Rayleigh waves, and surface wave dispersion measurements. Our results reveal a highly variable crustal structure across Myanmar region, characterized by a series of N‐S trending sedimentary basins, with thicknesses up to ~15 km in central Myanmar and an ~5‐km step in the depth of the Moho across the Sagaing‐Shan Scarp fault system. We interpolate our station‐based 1‐D velocity profiles to obtain an integrated 3‐D velocity model from southern Bangladesh to Myanmar. Using three regional earthquakes located to the south, within, and north of the seismic network, we show that our proposed model performs systematically better than the CRUST 1.0 model for both Pnl waves and surface waves. Our study provides a preliminary community velocity model for the region, with further refinements and interpretations anticipated in the near future.

Insights on the Source of the 28 September 2018 Sulawesi Tsunami, Indonesia Based on Spectral Analyses and Numerical Simulations

The 28 September 2018 Sulawesi tsunami has been a puzzle because extreme deadly tsunami waves were generated following an Mw 7.5 strike-slip earthquake, while such earthquakes are not usually considered to produce large tsunamis. Here, we obtained, processed and analyzed two sea level records of the tsunami in the near-field (Pantoloan located inside the Palu Bay) and far-field (Mamuju located outside the Palu Bay) and conducted numerical simulations to shed light on the tsunami source. The two tide gauges recorded maximum tsunami trough-to-crest heights of 380 and 24 cm, respectively, with respective dominating wave periods of 3.6−4.4 and 10 min, and respective high-energy wave duration of 5.5 and >14 h. The two observed waveforms were significantly different with wave amplitude and period ratios of ~16 and ~3, respectively. We infer tsunamigenic source dimensions of 3.4–4.1 km and 32.5 km, for inside and outside of the Palu Bay, respectively. Our numerical simulations fairly well reproduced both tsunami observations in Pantoloan and Mamuju; except for the arrival time in Mamuju. However, it was incapable of reproducing the maximum reported coastal amplitudes of 6–11 m. It is possible that these two sources are different parts of the same tectonic source. A bay oscillation mode of ~85 min was revealed for the Palu Bay through numerical modeling. Actual sea surface disturbances and landslide-generated waves were captured by two video recordings from inside the Palu Bay shortly after the earthquake. It is possible that a large submarine landslide contributed to and intensified the Sulawesi tsunami. We identify the southern part of the Palu Bay, around the latitude of -0.82oS, as the most likely location of a potential landslide based on our backward tsunami ray tracing analysis. However, marine geological data from the Palu Bay are required to confirm such hypothesis.

Effects of channel configuration on hydrothermal performance of the cylindrical mini-channel heat sinks

This work presents the numerical and experimental studies of the thermal and hydraulic performances of cylindrical mini-channel heat sinks (CMCHSs) based on the constructal theory and the entransy principle. Helical and wavy channels were proposed to enhance the heat transfer of CMCHSs in comparison with a conventional channel configuration (straight channel). A numerical simulation was performed using a three-dimensional finite volume method. On the basis of constructal theory, five degrees of freedom (DOFs) were presented, analyzed and discussed to show the geometrical impacts on the performance of CMCHSs when the laminar flow of water was less than 500. The DOFs of the design were channel configuration (straight, helical and wavy), channel aspect ratio (0.467–4), solid void fraction (80%, 85% and 90%), pitch ratio (1.5, 1.8, 2.1, 2.4 and 2.7) and wave amplitude ratio (0.032, 0.048, 0.062, 0.080 and 0.095). The experimental work examined the impacts of parameters on the thermal performance of fabricated CMCHSs with the optimum channel dimensions obtained from predicted numerical simulation and validated the computational simulation. In addition to the energy analysis of the performance of CMCHSs, a performance analysis was also conducted according to the entransy principle to determine the lowest entransy dissipation rate (EDR) and entransy dissipation thermal resistance. The numerical predicted results corroborated that DOFs have significant impacts on the performance of CMCHSs. The best solid void fraction and channel aspect ratio are 90% and 0.46, respectively. For the proposed CMCHSs with helical and wavy channels, Nusselt number and friction factor ratios increase with the increase of pitch and amplitude ratios. The preferred pitch and amplitude ratios are 2.1 and 0.08 because of their high-performance factor. The comparison between the channel configurations affirmed that the slight difference is in the values of the total EDR amongst the three channels. Moreover, the comparison of the best thermo-hydraulic performance of CMCHSs between helical and wavy channels indicated that the best performance was achieved in the helical channel with the lowest total EDR.

Influences of interface properties on the wave propagation in the dipolar gradient elastic solid

The present work mainly focuses on the influence of interface material parameters, namely the interface mass density, the interface elastic rigidity, and the interface inertial interaction constants, on the reflection and transmission behavior of elastic wave propagating through dipolar gradient elastic solids. First, the interface kinetic energy density and interface deformation energy density are taken into account. By application of Hamilton’s variation principle, the governing equations and the boundary conditions of the dipolar gradient elastic solid are obtained. Due to the consideration of microstructure effects of the material, the interface conditions can be proposed in different forms. These interfacial conditions which include the microstructure effects and interface energy effects are then used to determine the amplitude ratio of reflection and transmission waves. A numerical example is provided for the generalized internal roller interface. The influence of the interface material parameters upon the reflection and transmission coefficients in terms of energy fluxes ratio is discussed based on the numerical results. It is revealed that the reflection and transmission behavior can be manipulated by the elaborated design of the interface at both the macroscale and the microscale.

Comparison between the first and second wave crest amplitude generated by landslides

The landslide-generated wave which is largest is of particular interest due to hazard prevention. Among all wave trains, the first or second wave crest has the maximum amplitude. Whether the first wave crest amplitude is larger or not is undoubtedly affected by the landslide dimension and impact velocity. This paper presents a criterion for comparison between the first and second wave crest amplitude. 49 test runs are carried out based on an orthogonal design array, and in 39 runs wave crest amplitudes of the second waves are larger than those of the first waves. This study systematically investigates the effects of dimensionless front area, dimensionless top area, dimensionless two-dimensional volume and dimensionless three-dimensional volume on wave crest amplitude and wave amplitude ratio. An optimal criterion, including slide Froude number and dimensionless two-dimensional volume of slide, is proposed to determine which wave crest has the larger amplitude. The criterion is well verified by 157 test runs of two previous experiments.

Heat transfer and entropy generation of the nanofluid flow inside sinusoidal wavy channels

Corrugating channel walls is a way to enhance heat transfer in heat exchangers. In the current investigation, the entropy generation minimization approach has been employed to optimize heat transfer and fluid flow within a wavy channel. A numerical method has been built to compute entropy generation rate in a sinusoidal wavy-wall channel with copper-water (Cu-water) nanofluid flow. The governing equations have been discretized using finite volume method for a two-dimensional steady flow. The effects of geometrical and flow parameters, including nanoparticles volume fraction (0.01 < ϕ < 0.05), Richardson number (0.1 < Ri < 10), wave amplitude ratio (0.1 < α < 0.3) and wave length ratio (1 < λ < 3), have been investigated. Results reveal that increasing nanoparticle volume fraction within investigated Richardson number will increase Nusselt number. In addition, the maximum entropy generation rate declines as Richarson number increases. The optimal wave amplitude ratio (corresponding to lowest entropy generation), for wave length ratios of λ = 1 and λ = 2, found to be α = 0.2. Also, for wave length ratio of λ = 3, the minimum entropy generation approximately occurs at α = 0.1.