Adiabatic Effectiveness Research Articles

Overall effectiveness of film-cooled leading edge model with normal and tangential impinging jets

This paper investigates the overall effectiveness of film-cooled leading edge model with normal and tangential impinging jets. The leading edge has three rows of cylindrical film cooling holes, located at the stagnation line (0°) and ± 40° measured from the stagnation line. Film cooling holes are at an inclined angle of 25° relatives to the surface. The normal jet has one row of normal jet impinging holes and the tangential jet has two rows of tangential jet impinging holes. Mainstream Reynolds number based on the leading edge cylinder external diameter is about 100,000, and the mainstream turbulence intensity is about 7%. Three blowing ratios of 0.77, 1.54, and 2.31 are considered. Pressure sensitive paint technique is applied to measure the adiabatic effectiveness with the density ratio of 0.97. Liquid crystal technique is used to obtain the overall effectiveness with the density ratio of 0.94. Numerical simulations using realizable k-ɛ (RKE) turbulence model with enhanced wall treatment were applied to calculate the adiabatic effectiveness and overall effectiveness. Compared with experiments, numerical simulations overpredict overall effectiveness about 20% to 30% between the 0° row and the 40° row, and the difference between simulations and experiments is about 10% to 20% after the 40° row. The results provide baseline information for turbine blade leading edge film cooling design and heat transfer analysis.

Combined Experimental and CFD Investigation of Flat Plate Film Cooling through Fan Shaped Holes

The present paper reports the results of an experimental and computational investigation of flat plate film cooling jets discharged from three fan-shaped holes. Measurements have been carried out at near unity density ratio in a low-speed wind tunnel, at low inlet turbulence intensity, with blowing ratios (BR) of 1 and 2. Aerodynamic results have shown that the jet stays attached to the flat plate. Thermal measurements have revealed that film cooling effectiveness decreases downstream of the holes, and BR equal to 1 provides the best trade-off between cooling air consumption and thermal protection. Consequently, BR = 1 was selected for assessing the performance of different turbulence models, implemented in STAR-CCM+, according with the steady Reynolds-averaged Navier–Stokes (RANS) approach. Predictions from realizable k-ε (RKE), shear stress transport k-ω (SST KW) and Reynolds stress model (RSM) were compared against measurements of laterally averaged and centerline adiabatic effectiveness, as well as off-the-wall velocity maps and profiles of stress components. RSM provided the most accurate predictions.

Thermodynamic controls of the Western Tibetan Vortex on Tibetan air temperature

The “Western Tibetan Vortex” (WTV)—also termed the Karakoram Vortex—dominates the middle-to-lower troposphere and the near-surface air temperature variability above the western Tibetan Plateau (TP). Here, we explore the thermodynamic mechanisms through which the WTV modulates air temperature over the western TP by diagnosing the three major terms of the thermodynamic energy equation—adiabatic heating, horizontal temperature advection, and diabatic heating—that maintain the atmospheric thermal balance. We composite these major terms to examine the differences between anti-cyclonic and cyclonic WTV events. Our theoretical approach demonstrates that adiabatic sinking-compression (rising-expansion) provides the overwhelming control on both the middle-to-lower tropospheric and lower stratospheric temperature increases (decreases) under anti-cyclonic (cyclonic) WTV conditions over the western TP high mountain area in all four seasons. This also explains the mechanisms behind the anomalous temperature “dipole” found between the mid-lower troposphere and lower stratosphere when the WTV was initially identified. Spatially, adiabatic heating effects are centred on the central western TP in summer and the south slope centring at 70°–80°E of the TP in other seasons. The other two terms, horizontal temperature advection and diabatic heating, have localized importance over the edges of the western TP. In a case study over the Karakoram area, we further demonstrate that adiabatic heating (rising-expanding-cooling/sinking-compressing-warming) is the dominant thermodynamic process controlling Karakoram air temperatures under WTV variability, except for at the very near surface in autumn and winter. Our analysis methods can be applied to investigate the thermodynamic processes of other atmospheric circulation systems or climate variability modes.

Ab initio structure and vibration-rotation dynamics of germylene, GeH2.

Accurate structure and potential energy surface of germylene, GeH2 , in its ground electronic state 1 A1 were determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent basis sets up to sextuple-zeta quality. The Born-Oppenheimer equilibrium structural parameters for the 1 A1 state are estimated to be re (GeH) = 1.5793 Å and ∠e (HGeH) = 91.19∘ . The term value Te for the lowest excited electronic state ã3 B1 of GeH2 is predicted to be 9140 cm-1 . The vibration-rotation energy levels for the 1 A1 state of the 74 GeH2 , 74 GeD2 , 72 GeH2 , and 70 GeH2 isotopologues were determined using a variational approach and compared with the experimental data. The role of the core-electron correlation, higher-order valence-electron correlation, scalar relativistic, spin-orbit, and adiabatic effects for prediction of the structure and vibration-rotation dynamics of the GeH2 molecule is discussed. © 2019 Wiley Periodicals, Inc.

Effect of Ingress on Flow and Heat Transfer Upstream and Downstream of a Rotating Turbine Disc

Ingress is the penetration of a hot mainstream gas in a turbine annulus through the rim seal into the wheel-space between the rotating turbine disc (the rotor) and the adjacent stationary casing (the stator). Purge flow is used to prevent or reduce ingress, and the sealing effectiveness relates the flow rates of the purge and ingress. In this paper, an adiabatic effectiveness is used to relate the temperatures of a thermally-insulated rotor, the purge flow and the ingress. A non-dimensional buffer parameter, Ψ, is used to relate the sealing effectiveness on the stator and the adiabatic effectiveness on the rotor, respectively. This paper reports the first experimental study of the effect of ingress and purge flow on the adiabatic temperatures of both upstream and downstream surfaces of the rotor. Measurements of concentration and swirl over a range of purge have been obtained in wheel-spaces upstream and downstream of the rotor in a turbine rig. In transient heating tests, fast-response thermocouples were used to measure the temperature of the air in the wheel-space core; simultaneously, the temperatures of the upstream and downstream rotor surfaces were determined from infra-red sensors. The extrapolated steady-state temperatures (obtained using a maximum-likelihood estimation analysis) were used to determine the adiabatic effectiveness as a function of purge flow rate. The buffer effect of the purge flow for both wheel-spaces was quantified via comparisons between the variation of Ψ with purge flow rate. It was shown that the sealing effectiveness for the downstream wheel-space was larger than for the upstream. Consequently, and consistent with the theoretical model, the buffering effect of the purge flow was shown to be smaller downstream.

Ab initio structure and vibration-rotation dynamics of the formyl and isoformyl cations, HCO+/HOC.

Accurate structure and potential energy surface of the formyl and isoformyl cation system, HCO+/HOC+, in its ground electronic state X̃ 1Σ+ have been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent basis sets up to septuple-zeta quality. Both the isomers are confirmed to be linear at equilibrium, with the total energy minimum of HOC+ lying 14 120 cm-1 above that of HCO+ and the HCO+ → HOC+ isomerization energy barrier being 26 870 cm-1 (in the Born-Oppenheimer approximation). The equilibrium structural parameters for HCO+ are estimated to be re(HC) = 1.0919 Å and re(CO) = 1.1058 Å, whereas those for HOC+ are estimated to be re(HO) = 0.9899 Å and re(CO) = 1.1544 Å. The vibration-rotation energy levels were predicted for various isotopologues using a variational approach and compared with the experimental data. For the spectroscopically well characterized formyl cation, the observed vibration-rotation energies and the effective rotational constants are reproduced to within about 2.3 cm-1 and 1.7 MHz, respectively. The role of the core-electron correlation, higher-order valence-electron correlation, scalar relativistic, and adiabatic effects in determining the structure and vibration-rotation dynamics of both the isomers is discussed.

Numerical evaluation of showerhead film cooling aerothermal performance on a first-stage vane

A wide set of experimental data has been used to validate numerical simulations of leading edge film cooling in a high-pressure turbine vane, according with steady-state RANS and delayed detached-eddy simulation (DDES) modelling. A typical showerhead configuration was adopted, namely 4 staggered rows of cylindrical holes. Boundary conditions were fully based on the wind tunnel tests: low speed flow (exit isentropic Mach number of Ma2is = 0.2), low inlet turbulence intensity of Tu1 = 1.6% and low density ratio of DR ∼ 1 were dictated by constraints relating to Particle Image Velocimetry (PIV) setup. One only blowing ratio of BR = 3.0 was taken into account since it is representative of effective thermal protection, while offering a challenging scenario of jet separation and reattachment on a curved surface. Predicted off-the-wall aerodynamic features of the flow in the leading edge region were compared against PIV data and flow visualizations. Moreover, contours of adiabatic effectiveness, measured with the pressure sensitive paint (PSP) technique by injecting nitrogen as coolant (DR ∼ 1), were computed by means of the species transport model (i.e. mass transfer (MT)), in addition to the conventional thermal method (i.e. heat transfer (HT)). The MT approach yielded more accurate predictions of adiabatic effectiveness (η) than the alternative HT method. Therefore it can be considered particularly suited to the validation of the PSP experimental results. DDES was indispensable to capture the highly unsteady, anisotropic mixing of the cooling jets with the mainstream, despite overestimation of the jet vertical penetration, and hence slight underprediction of η outside the showerhead region.

Investigation on dynamic hardness and high strain rate indentation size effects in aluminium (110) using nano-impact

Nano-impact, a high strain rate pendulum-based indentation technique, has been widely used to extract the local dynamic mechanical response of materials in repetitive contact. In contrast the analysis of single high strain rate impacts to obtain quantitative information on strain rate sensitivity is less well developed. A robust and reliable method for determining dynamic hardness at the nano- and micro-scale is highly desirable. In the present work, nano-impacts with different accelerating force and distance were carried out on a sample of single crystal Al (110) to study the dynamic hardness and its size effects. The common energy-based approach for dynamic hardness has been compared with an approach using Meyer's hardness corresponding to the ratio of the recorded peak force and the projected area of the indentation. It was found that both methods showed broadly similar values at larger penetration depth, but the energy approach became less reliable at the low impacting energy due to unavoidable energy dissipation in the system. Dynamic indentation size effects have been identified which were more pronounced than those in quasi-static indentation tests. This dynamic effect has been attributed to the localized strain caused by the high strain rate and its rapid change during contact. At the highest impact energies studied a transition into strain softening was also identified which is probably due to the adiabatic effects caused by the localized strain under severe impacting conditions.

Adiabatic effects on the temperature and rate dependency of the fracture toughness of an ethylene-fluoroethylene film

In this work, the essential work of fracture (EWF) test has been applied to determine the temperature and strain-rate dependency of the fracture toughness of ethylene-fluoroethylene (ETFE) thin films.EWF tests were conducted at different temperatures (23, 50 and 80 °C) and different cross-head rates (1, 10, and 100 mm/min). At 23 °C, the specific essential work of fracture (we) values slightly increase as the strain rate increases, while at 50 °C and 80 °C we values decrease. This trend is associated to an increase of the specific essential work for crack propagation (we,prop) while the specific essential work for crack initiation (we,init) decreases with strain rate with a magnitude related to the testing temperature. Thermal observations with an infrared camera revealed an increase of the temperature at the crack tip for the highest strain rate, thus suggesting, for the sample tested at the lowest temperature, the concurrent effects of strain-rate embrittlement and adiabatic heating. Digital image correlation (DIC) analysis revealed an ovoid shape of the outer plastic zone (OPZ) prior to the start of the crack propagation. DIC also indicated that the extension of the OPZ increases linearly with the square of the ligament length.

Study of the Dynamic Recrystallization Process of the Inconel625 Alloy at a High Strain Rate.

High-temperature compression and electron backscatter diffraction (EBSD) techniques were used in a systematic investigation of the dynamic recrystallization (DRX) behavior and texture evolution of the Inconel625 alloy. The true stress–true strain curves and the constitutive equation of Inconel625 were obtained at temperatures ranging from 900 to 1200 °C and strain rates of 10, 1, 0.1, and 0.01 s−1. The adiabatic heating effect was observed during the hot compression process. At a high strain rate, as the temperature increased, the grains initially refined and then grew, and the proportion of high-angle grain boundaries increased. The volume fraction of the dynamic recrystallization increased. Most of the grains were randomly distributed and the proportion of recrystallized texture components first increased and then decreased. Complete dynamic recrystallization occurred at 1100 °C, where the recrystallized volume fraction and the random distribution ratios of grains reached a maximum. This study indicated that the dynamic recrystallization mechanism of the Inconel625 alloy at a high strain rate included continuous dynamic recrystallization with subgrain merging and rotation, and discontinuous dynamic recrystallization with bulging grain boundary induced by twinning. The latter mechanism was less dominant.

The electron couplings in the transition states: The stereodynamics of state to state autoionization processes.

Measurements of the kinetic energy distribution of electrons, emitted in collision between Ne*(3P2,0) and Kr(1S0) and Xe(1S0), have been performed in a crossed molecular beam apparatus which employs a mass spectrometer and a hemispherical electron analyzer as detectors. The analysis of the obtained experimental results provides new insights on electronic rearrangements and electronic angular momentum coupling effects that determine relevant properties of the transition state of autoionization processes, and that we have found useful to classify as adiabatic and non-adiabatic effects. In particular, while the adiabatic effects control sequence, energy, and symmetry of quantum states accessible to both reagents and products in the probed collision energy range, the non-adiabatic ones trigger the passage from entrance to exit channels. The obtained results are important not only to compact previous theoretical schemes of autoionization reactions in a unified representation but also to cast light on the role of electronic rearrangements within the transition state of many other types of chemical processes that are more difficult to characterize.

Effects of deformation–induced BCC martensitic transformation and twinning on impact toughness and dynamic tensile response in metastable VCrFeCoNi high–entropy alloy

The metastable high- and medium entropy alloys (HEAs or MEAs) have drawn many attentions regarding deformation mechanisms and mechanical properties. Most of their studies have conducted under quasi–static or uniaxial tensile/compressive loading conditions. For cryogenic applications, however, the fracture or impact toughness should be carefully evaluated because it is one of the most important indices for the low–temperature performance. In this study, quasi–static and dynamic tensile properties of a metastable VCrFeCoNi HEA were investigated at room and cryogenic temperatures, and they were systematically correlated with the Charpy impact toughness. Under the quasi–static tensile loading, the Twinning Induced Plasticity (TWIP) mechanism occurred at room temperature, while the Transformation Induced Plasticity (TRIP) from FCC to BCC phases via an intermediate HCP phase occurred at cryogenic temperature. Under the dynamic loading, more deformation twins were formed at room temperature, and the amount of martensite reduced at cryogenic temperature. These variations of twinning and martensitic transformation were elucidated by the raised flow stress and by the adiabatic heating effect, respectively. They were confirmed by combining with ab–initio calculations, leading to the strong dependency of the energetic stability of BCC and HCP phases relative to the FCC phase. As a result, a plenty of deformation twins under the dynamic loading resulted in the high impact toughness of 112.6 J at room temperature. The martensitic transformation and consequently refined network structure played key roles in sustaining the remarkable toughness and in preventing the DBT phenomenon as the test temperature decreased.

Computational study of film cooling and flowfields on a stepped vane endwall with a row of cylindrical hole and interrupted slot injections

Endwall is one of the critical regions to perform film cooling for gas turbine because of not only the increase of turbine inlet temperature but also the complicated secondary flow. Typical endwall film cooling configuration includes leakage slot at combustor-vane interface and discrete cooling holes on the wall. This paper mainly studied the effect of endwall step on the cooling performance of downstream cooling holes. The combustor-turbine interface in this paper is a kind of backward-facing step, causing an interrupted slot. The detailed characteristic of the interrupted slot has been investigated in the previous study. Three dimensional Reynolds-averaged Navier-Stokes equations with shear stress turbulence model (SST) k-ω was solved to perform the calculations of endwall film effectiveness. The adiabatic film effectiveness on the flat endwall was compared with that on the stepped endwall with and without the interrupted slot. Results showed a significant impact of the endwall step on the adiabatic film cooling effectiveness. Coolant jet downstream of the step is split into two parts due to the effects of step vortex (SV) and cross flow. Detailed flowfields in spanwise, pitchwise and axial planes explain the formation and development of secondary flow near the cooling holes. For a range of blowing ratio from 0.6 to 1.2, increasing the blowing ratio of cooling holes deteriorates the adiabatic film cooling effectiveness upstream and downstream of the cooling holes due to the jet liftoff. It is found that cooling effectiveness is strongly dependent on the axial position of the hole. Placing the cooling holes downstream at leading edge plane of the cascade little effect of the step vortex on the film effectiveness and, subsequently, relatively uniform coolant coverage was observed on the endwall.

Cooling Effectiveness for a Shaped Film Cooling Hole at a Range of Compound Angles

Shaped film cooling holes are a well-established cooling technique used in gas turbines to keep component metal temperatures in an acceptable range. One of the goals of film cooling is to reduce the driving temperature for convection at the wall, the success of which is generally represented by the film cooling adiabatic effectiveness. However, the introduction of a film cooling jet-in-crossflow, especially if it is oriented at a compound angle, can augment the convective heat transfer coefficient and dominate the flowfield. This work aims to understand the effect that a compound angle has on the flowfield and adiabatic effectiveness of a shaped film cooling hole. Five orientations of the public 7–7–7 shaped film cooling hole were tested, from a streamwise-oriented hole (0 deg compound angle) to a 60 deg compound angle hole, in increments of 15 deg. Additionally, two pitchwise spacings of P/D = 3 and 6 were tested to examine the effect of hole-to-hole interaction. All cases were tested at a density ratio of 1.2 and blowing ratios ranging from 1.0 to 4.0. The experimental results show that increasing compound angle leads to increased lateral spread of coolant and enables higher laterally averaged effectiveness at high-blowing ratios. A smaller pitchwise spacing leads to more complete coverage of the endwall and has higher laterally averaged effectiveness even when normalized by coverage ratio, suggesting that hole to hole interaction is important for compound angled holes. Steady Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) was not able to capture the exact effectiveness levels, but did predict many of the observed trends. The lateral motion of the coolant jet was also quantified, both from the experimental data and the CFD prediction, and as expected, holes with a higher compound angle and higher blowing ratio have greater lateral motion, which generally also promotes hole-to-hole interaction.

Experimental Study of Periodic Free Stream Unsteadiness Effects on Discrete Hole Film Cooling in Two Geometries

Discrete hole film cooling is widely employed to protect turbine blades and vanes from hot combustion gases entering the high-pressure turbine stage. Accurate prediction of the heat transfer near film cooling holes is critical, and high-fidelity experimental data sets are needed for validation of new computational models. Relatively few studies have examined the effects of periodic main flow unsteadiness resulting from the interaction of turbine blades and vanes, with a particular lack of data for shaped hole configurations. Periodic unsteadiness was generated in the main flow over a laidback, fan-shaped cooling hole at a Strouhal number (St = fD/U) of 0.014 by an airfoil oscillating in pitch. Magnetic resonance imaging (MRI) with water as the working fluid was used to obtain full-field, phase-resolved velocity and scalar concentration data. Operating conditions consisted of a hole Reynolds number of 2900, channel Reynolds number of 25, 000, and blowing ratio of unity. Both mean and phase-resolved data are compared to the previous measurements for the same hole geometry with steady main flow. Under unsteady freestream conditions, the flow separation pattern inside the hole was observed to change from an asymmetric separation bubble to two symmetric bubbles. The periodic unsteadiness was characterized by alternating periods of slow main flow, which allowed the coolant to penetrate into the freestream along the centerplane, and fast, hole-impinging main flow, which deflected coolant toward the laidback wall and caused ejection of coolant from the hole away from the centerplane. Mean adiabatic surface effectiveness was reduced up to 23% inside the hole, while mean laterally averaged effectiveness outside the hole fell 28–36% over the entire measurement domain. A brief comparison to a round jet with and without unsteadiness is included; for the round jet, no disturbance was observed inside the hole, and some fluctuations directed coolant toward the wall, which increased mean film cooling effectiveness. The combined velocity and concentration data for both cases are suitable for quantitative validation of computational fluid dynamics predictions for film cooling flows with periodic freestream unsteadiness.

Anomalous acoustic phonons as the physical mechanism behind the adiabatic barocaloric effect on graphene

A graphene sheet is able to either heat up or cool down due to a mechanical strain: this is the adiabatic barocaloric effect. In order to understand the physical mechanism behind this effect, we have explored the adiabatic temperature change of the graphene and, for this purpose, we considered two contributions to the total entropy: a lattice entropy (depending on the transversal, longitudinal and anomalous out-of-plane acoustic phonons) and a strain entropy. We found that the adiabatic barocaloric effect only depends on the strain energy and the anomalous acoustic phonons, without terms due to the transversal and longitudinal acoustic phonons.

Sweeping Jet Film Cooling on a Turbine Vane

The cooling performance of sweeping jet film cooling was studied on a turbine vane suction surface in a low-speed linear cascade wind tunnel. The sweeping jet holes consist of fluidic oscillators with an aspect ratio (AR) of unity and a hole spacing of Pd/D = 6. Infrared (IR) thermography was used to estimate the adiabatic film effectiveness at several blowing ratios and two different freestream turbulence levels (Tu = 0.3% and 6.1%). Convective heat transfer coefficient was measured by a transient IR technique, and the net heat flux benefit was calculated. The total pressure loss due to sweeping jet film cooling was characterized by traversing a total pressure probe at the exit plane of the cascade. Tests were performed with a baseline shaped hole (SH) (777-shaped hole) for comparison. The sweeping jet hole showed higher adiabatic film effectiveness than the 777-shaped hole in the near hole region. Although the unsteady sweeping action of the jet augments heat transfer, the net positive cooling benefit is higher for sweeping jet holes compared to 777 hole at particular flow conditions. The total pressure loss measurement showed a 12% increase in total pressure loss at a blowing ratio of M = 1.5 for sweeping jet hole, while 777-shaped hole showed a 8% total pressure loss increase at the corresponding blowing ratio.

Quantum-Classical Correspondence for Adiabatic Shortcut in Two- and Three-Level Atoms

The methods of quickly achieving the adiabatic effect through a non-adiabatic process has recently drawn widely attention both in quantum and classical regime. In this work ,we study the classical adiabatic shortcut for two- and three-Level atoms by transforming the quantum version into classical one via quantum-classical corresponding theory. The results shows that, the additional couplings between the oscillators can be used to speed up the adiabatic evolution of coupled oscillators. Furthermore, we find that the quantum-classical correspondence theory still holds for the couter-adiabatic driving Hamiltonian for the TQD. This means that, we can obtain the counter-adiabatic driving Hamiltonian for a classical system by averaging over its quantum correspondence in a quantum system. This provides a feasible way to study the classical adiabatic shortcut and the simulation for the quantum adiabatic shortcut in a classical system.

Analyses of the structure of wave functions and energies spectra of ground and low excited states of Ytterbium isotopes

Abstract Non – adiabatic effects in wave functions and energy spectra of ground (gr) 0 2 + ( β 1 ) , 0 3 + ( β 2 ) , 2 1 + ( γ 1 ) , 2 2 + ( γ 2 ) and K π = 1 ν + rotational bands of 170;172;174Yb isotopes are studied, within the phenomenological model, which takes into account the mixing of ground 0 2 + ( β 1 ) , 0 3 + ( β 2 ) , 2 1 + ( γ 1 ) , 2 2 + ( γ 2 ) and K π = 1 ν + rotational bands. The wave functions and energy of ground and low excited states are calculated. The finding reveals that the mixture of bands have been found to considerable impact on the wave functions of low – lying states of 0 m + and 2 l + bands.

Fully nonlinear simple internal waves over subcritical slopes in continuously stratified fluids: Theoretical development

The dynamics of fully nonlinear internal waves in continuously stratified fluids is investigated using a new simple-wave (or Riemann-wave) theory with 2nd-order topographic effects. Unlike previous fully nonlinear internal-wave theories, the proposed theory is applicable to large water-depth change over a long distance, provided that the local bottom slopes are mild. An essential step in the theoretical development is the separation of “adiabatic” and “diabatic” topographic effects. First, adiabatic topographic effects are incorporated into the previous simple-wave theory, in such a way that one-directional, fully nonlinear, nondispersive waves become conservative over topography. Since the Riemann variable (or invariant) remains constant along the characteristic, this extends the applicability of the solution method based on characteristic curves from flat bottom to mild slopes. Then, 2nd-order diabatic topographic effects are added to the adiabatic simple-wave solution by a perturbation approach. The application of the proposed theory to Wunsch’s subcritical wedge problem suggests that the proposed theory is applicable to subcritical slopes, although the error unavoidably increases as the slope angle approaches the propagation angle of internal wave rays (i.e., the critical angle). An important finding is the relatively rapid growths of wave-induced isopycnal setup and mean flow under the combined effects of strong nonlinearity and topography, in contrast to temporally stationary setup and mean flow under weak topographic effects. This implies, for example, that large-amplitude internal waves on continental shelves have an inherent tendency to modify the “background” stratification and currents without mixing and that it could occur within a spring-neap tidal cycle.