Frequency Of Disk Research Articles

EXPERIMENTAL DEVELOPMENT OF DISC GRAIN MILL

In the structure of the product's production, feed is in the first place and accounts for 60-70% of the total cost. The effectiveness of stagnation of concentrated feed depends on the quality of their preparation, and the uniformity of detail and type of fractional stock of animal husbandry products. In the midst of all the development of methods of refinement and design solutions for the greatest expansion for the refinement of feed grain, hammer mills have emerged, which, unlike any other in the world, provide energy saving, with fine grinding up to 40% of the saw-like fraction, and for coarse grains - up to 20% of whole and incomplete grains. At the same time, disk-type grain trimming designs are becoming more and more widespread in the world. Such structures are developed from hammer construction with lower energy consumption and higher yield of the finished product. Therefore, further research aimed at improving the efficiency of the work of disk workers is relevant. Experimental studies of disk grain processing were carried out based on the theoretical design of the experiment, which was why mathematical models of processes were selected in the form of regression. The factors in the experiment were the frequency of disk wrapping n (x1), the modular gap between the disks m (x2) and the moisture content of the grain W (x3). Optimization criteria are the energy density of the detail q (y1) and the uniformity of k (y2). The energy intensity of the process began as a balance between effort and productivity. Uniformity began as a relationship instead of often with rational parameters to the point of importance and was expressed in hundreds. As a result of experimental studies of disk grain processing, it has been established that the energy intensity of the process and the uniformity of the grain are dependent on all relevant factors, with which rational indicators are based on optimization criteria and do not match. The main task is to find the optimal variation of factors for two criteria, which makes it possible to confirm that the minimum energy intensity of the process is in the range q = 3.67…4.54 kWhour/t, one Particularity - k=86.5…92.6% at values of additional factors n=1260-1320 min-1; W=12.8-13.2% for a rational range of refinement steps.

Vibration Analysis of Thin Circular Disc Interacting With A Fluid in Cylindrical Container

In this paper, vibration analysis of a thin circular disc interacting with a fluid in cylindrical container is carried out. It has been done systematically by carrying our mathematical modeling and subsequently validated by ANSYS software. The author has first determined natural frequencies and mode shapes for a thin circular disc alone and then for fluid contained by a cylindrical vessel alone. The author had then found natural frequencies and mode shapes for coupled case of thin circular disc interacting with a fluid contained by the cylindrical container. The same had been validated by ANSYS software. It is found that natural frequencies of coupled vibrations are different than that of the frequency of disc or fluid taken separately. In order to study the correct failure pattern of the coupled vibration system, it, thus, becomes a necessity to study coupled vibration analysis

Термообработка слизистых субпродуктов под воздействием электрофизических факторов: разработка установки

Low efficiency of equipment for heat treatment, disinfection and removal of unpleasant odour of substandard mucous by-products urges the development of an installation that provides for the complex effect of ultra-high frequency electromagnetic field, ozone and bactericidal flow of ultraviolet rays. The paper presents the technology and describes the installation developed by the authors. The installation ensures electromagnetic safety and uniformity of loading according to the penetration depth of the wave. The duration of raw material treatment is matched with the specific power of the microwave generator, the power of the lamps and with the rotation frequency of the compartment disc. The electric field strength has been studied in the CST Microwave Studio program. The developed installation contains a resonator in the form of a flattened spheroid with diameters of the main axes multiple of half the wavelength. Magnetrons are placed on the upper surface of the spheroid along the perimeter. On the inner surface of the spheroid, where there are corona needles, ring electro-gas-discharge lamps powered from pulsed modeled high-frequency generators are uniformly installed along the perimeter through the gap. The source of radiation in the bactericidal lamp is an electric discharge in a mixture of mercury vapour and argon. A fluoroplastic perforated disc is installed at the level of the large diameter of the spheroid, on which mucous by-products are treated. The conducted research shows that the intrinsic factor of quality of the spheroid resonator is 9000. The heat treatment and disinfection of raw materials is most effective at the plant productivity of 50 kg/h, electric field strength of 3 to 4 kV/cm, disc rotation frequency of 0.17 to 0.2 rpm and a specific power of the microwave generator of 1.2 W/g. Power consumption amounted to 6.6 kW, while energy costs were 0.132 kW∙h/kg.

Computer simulation for stability analysis of the viscoelastic annular plate with reinforced concrete face sheets

This article deals with the frequency analysis of viscoelastic sandwich disk with graphene nano-platelets (GPLs) reinforced viscoelastic concrete (GPLRVC) face sheets and honeycomb core. The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the concrete. By employing Hamilton's principle, the governing equations of the structure are derived and solved with the aid of the Generalize Differential Quadrature Method (GDQM). In this paper, viscoelastic properties are modeled according to Kelvin-Voigt viscoelasticity. The deflection as the function of time can be solved by the fourth-order Runge-Kutta numerical method. Afterward, a parametric study is carried out to investigate the effects of the outer to inner radius ratio, hexagonal core angle, thickness to length ratio of the concrete, the weight fraction of GPLs into concrete, and the thickness of honeycomb core to inner radius ratio on the frequency of the viscoelastic sandwich disk with honeycomb core and FGGPLRVC face sheet.

Nonlinear frequency and chaotic motion of the honeycomb higher-order disk with graphene nanoplatelets face sheets subjected to harmonic excitation via two-dimensional analysis

Honeycomb structures are one type of structure that has the geometry of a honeycomb to allow the minimization of the amount of used material to reach minimal material cost and minimal weight. For this issue, in the current analysis, an attempt is made to develop the nonlinear mathematical model for the chaotic and large-amplitude motions of a sandwich disk with graphene nanoplatelet face sheets honeycomb core and subjected to external excitation. Using Hamilton’s principle, higher-order shear deformation theory (HSDT), and the Von-Karman nonlinear theory, the nonlinear governing equation is derived. The generalized differential quadrature method (GDQM) and perturbation approach (PA) are eventually used to develop a precise solution approach. This article’s fundamental and golden results are that for clamped–clamped boundary conditions, the softening of the system in zone 2 is less than zone 1, whereas the instable responses in zone 2 are more than zone 1. Also, for the sandwich disk with clamped–clamped boundary conditions, the system’s dynamic behavior tends to be more harmonious and less chaotic as the fiber’s angle increases. Therefore, increasing the fiber angle reduces the system’s chaos with clamped edges, which is very important for future works.

Frequency Domain Analysis of Partial-Tensor Rotating Accelerometer Gravity Gradiometer.

The output model of a rotating accelerometer gravity gradiometer (RAGG) established by the inertial dynamics method cannot reflect the change of signal frequency, and calibration sensitivity and self-gradient compensation effect for the RAGG is a very important stage in the development process that cannot be omitted. In this study, a model based on the outputs of accelerometers on the disc of RGAA is established to calculate the gravity gradient corresponding to the distance, through the study of the RAGG output influenced by a surrounding mass in the frequency domain. Taking particle, sphere, and cuboid as examples, the input-output models of gravity gradiometer are established based on the center gradient and four accelerometers, respectively. Simulation results show that, if the scale factors of the four accelerometers on the disk are the same, the output signal of the RAGG only contains ( is the spin frequency of disc for RAGG) harmonic components, and its amplitude is related to the orientation of the surrounding mass. Based on the results of numerical simulation of the three models, if the surrounding mass is close to the RAGG, the input-output models of gravity gradiometer are more accurate based on the four accelerometers. Finally, some advantages and disadvantages of cuboid and sphere are compared and some suggestions related to calibration and self-gradient compensation are given.

Investigation on the parameter sensitivity of bladed assemblies undergoing mistuning features

The present study's objectives are primarily to reveal the mistuning effects on the coupling system's nonlinear vibration performance with a mechanical model of the flexible bladed disk system. And the sensitivities of the coupling system to different mistuning cases are also compared and estimated. Firstly, the tuned system's nonlinear characteristics are presented for providing a reference to interpret the nonlinear dynamics of the mistuning case. Then present analysis exploits the nonlinear response spectrum of the coupling system undergoing a series of parameter mistuning conditions. The numerical simulation reveals that the response characteristics of cycle blades exhibit perfect identity in the tuned system. When the parameter mistuning condition occurs, the identity characteristics are destroyed, especially the blade length mistuning case. The mistuning feature can also lead to new resonances at the modal frequency of flexible disk, which exhibits distinctive sensitivity to the different mistuning case. Besides, the vibration localization phenomenon occurs due to the broken cyclic periodicity of the bladed disk structure. Furthermore, enough attention should be paid to the coupling effects in the bladed disk system undergoing parameter mistuning in engineering practice.

RETRACTED ARTICLE: Dynamic simulation of moderately thick annular system coupled with shape memory alloy and multi-phase nanocomposite face sheets

The current research work analyzes dynamics of a sandwich disk which is gently thick. The mentioned sandwich structure has honeycomb core, a couple of middle layers having fibers of shape memory alloy (SMA), and a couple of external layers of multi-scaled hybrid nanocomposite (MHC) considering in-plane force. The core in the shape of honeycomb is manufactured of aluminum due to its high stiffness and less density compared with other materials. Applying energy methods called the principle of Hamilton, we obtained governing motion equations of the mentioned structure and solved them using First-order shear-deformation-theory (FSDT), as well as generalized-differential-quadrature-method (GDQM), respectively. To layers’ joint, the compatibility equations have been taken into account. Then, a parametric mathematical manipulation has been conducted to analyze the impacts of fibers of SMA, boundary conditions (BCs), internal loads, honeycomb network angle, ratio of external to internal radiuses, ratio of thickness to length of the honeycomb, weight fraction of CNTs, angle of fibers, ratio of honeycomb to face-sheet thickness on the frequency of the multi-phase sandwich disk. The outcomes derived reveal that for any amount of internal pressure and each BCs, the relation of the honeycomb’s thickness ratios to MHC layer ( $${h}_{H}/{h}_{t}$$ ) and sandwich structure’s frequency is similar to quadratic function. Further results show that the effects of the fibers’ angle on the frequency can be ignored for larger $${h}_{H}/{h}_{t}$$ amounts.

Comparative analysis and differentiation between SAPHO syndrome and spondyloarthropathies using whole-spine MRI

To determine the imaging characteristics of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome and seronegative spondyloarthropathies (SpAs) on whole-spine magnetic resonance imaging (WS-MRI) and evaluate the role of WS-MRI in the diagnosis and differentiation of the two diseases. Twenty-eight patients with SAPHO and 44 with SpAs were included. All patients were symptomatic and clinically diagnosed with SAPHO or SpAs, and all underwent WS-MRI for comparison of imaging characteristics. The mean age of the SAPHO patients was 48.7±12.7 years, while that of the SpA patients was 34.7±12.3 years (p<0.001). WS-MRI showed that the frequency of cervical, thoracic, and lumbar spine involvement was 53.6% versus 52.3%, 75% versus 88.6%, and 60.7% versus 63.6%, respectively (p=0.70, 0.13, and 0.80). The frequency of sacroiliac joint involvement was 7.1% and 100% (p<0.001). Continuous spinal involvement accounted for 50% versus 43.2%, 60.7% versus 84.1%, and 39.3% versus 40.9% in the cervical, thoracic, and lumbar vertebrae, respectively (p=0.03). WS-MRI showed that bone marrow oedema of spinal anterior corner was observed in 50% versus 75% (p=0.03). Vertebral body and posterior attachment involvement accounted for 85.7% versus 93.2% and 14.3% versus 34.1% (p=0.3, 0.06). The frequency of bone erosion in mobile spine was 75% and 36.4%, respectively (p=0.02). The frequency of intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue swelling was 42.9% versus 18.2%, 53.6% versus 22.7%, 85.7% versus 42.2%, and 50% versus 11.4% (p=0.02, 0.00). Factors differentiating the two groups at WS-MRI were bone marrow oedema of the spinal anterior corner, bone erosion, and swelling of the intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue.

Blade Crack Detection using Blade Tip Timing

The harsh working environment of compressor threats the integrality of bladed disk. Crack is one of the most fatal faults of rotating blades. Detecting the crack of blades at early stage could ensure the safe operation of gas turbine and save economic costs. Blade tip timing (BTT) is a noncontact blade vibration measurement technique, which is widely used in recent years. In this article, a procedure of crack detection using BTT data is proposed. First, some typical parameters are taken into consideration, including resonance frequency, amplitude change of natural frequency, amplitude of blade tip, phase, and interblade spacing. It has been found that the frequency of the blade will decrease with the increment of crack length and reduction of crack height. In addition, the resonance frequency of the bladed disk will split when the blade cracks. The amplitude of different orders of resonance frequency varies with cracks. The amplitude of the first order changes very slightly, whereas the second and third orders are relatively obvious. The blade tip vibration amplitude and phase change with cracks without obvious regularity. The interblade distance will change due to the appearance of cracks. According to the above rules, the frequency and the interblade distance are adopted as crack diagnosis indicators. First, we use the Lomb-Scargle periodogram to quickly determine whether the crack appears and then use the blade frequency and interblade distance to locate the number of the blade having crack. In the experimental test, BTT data measured on a titanium bladed disk is used to verify the effectiveness of our method.

Semi-numerical simulation for vibrational responses of the viscoelastic imperfect annular system with honeycomb core under residual pressure

This composition investigates the frequency analysis of sandwich imperfect viscoelastic disks with graphene nano-platelets (GPLs)-reinforced viscoelastic composite (GPLRVC) face sheets and honeycomb core. The honeycomb core is made of aluminum because of its high stiffness and low weight. The modified Halpin-Tsai model and rule of the mixture have been utilized to provide the effective material constant of the composite layers. Through employing Hamilton's principle, the governing equations of the structure are accordingly discerned and resolved by utilizing the Generalized Differential Quadrature Method (GDQM). Throughout this investigation, viscoelastic properties have been modeled in accordance with Kelvin-Voigt viscoelasticity. The deflection as the function of time is capable of being resolved through employing the fourth-order Runge-Kutta numerical method. Afterwards, a parametric study is conducted to discern the effects of the FG patterns, outer to inner radius ratio, hexagonal core angle, thickness to length ratio of the GPLs, the weight fraction of GPLs, FG face sheet thickness ratio, the thickness of honeycomb core to inner radius ratio, tensile, imperfect coefficient, and in-plane force on the frequency of the sandwich viscoelastic disk with honeycomb core and FG-GPLRVC face sheet.

On the vibrations of the imperfect sandwich higher-order disk with a lactic core using generalize differential quadrature method

This article presents the frequency responses of a sandwich disk with a lactic core (honeycomb), two middle layers containing SMA fiber, and two outer layers (multi-scale hybrid nanocomposite (MHC)). The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the composite layers. By employing Hamilton’s principle, the governing equations of the structure are derived and solved with the aid of the generalized differential quadrature method (GDQM). Compatibility equations are considered for modeling the interface between the layers of the sandwich disk. Afterward, a parametric study is done to present the effects of SMA fiber, boundary conditions, outer to inner radius ratio, honeycomb network angle, thickness to length ratio of the honeycomb, fibers angle, weight fraction of CNTs, honeycomb to face sheet thickness ratio on the frequency of the multi-phase sandwich disk. The results show that employing the honeycomb network as the core of the structure improves the dynamic response of the structure, impressively. Another consequence is that if there are C-C, C-S boundary conditions, by ever-increase in the θh/π, the dynamic response tends to decline.

Periodicities in the K2 light curve of HP Librae

ABSTRACT We analyse Kepler/K2 light-curve data of the AM CVn system HP Librae (HP Lib). We detect with confidence four photometric periodicities in the system: the orbital frequency, both positive and negative superhumps, and the positive apsidal precession frequency of the accretion disc. This is only the second time that the apsidal precession frequency has ever been directly detected in the photometry of a helium accreting system, after SDSS J135154.46-064309.0. We present phase-folded light curves and sliding power spectra of each of the four periodicities. We measure rates of change of the positive superhump period of ∼10−7 d. We also redetect a quasi-periodic oscillation (QPO) at ∼300 cyc d–1, a feature that has been stable over decades, and show that it is harmonically related to two other QPOs, the lowest of which is centred on the superhump/orbital frequency. The continuum power spectrum is consistent with a single power law with no evidence of any breaks within our observed frequency range.

Influence of in-plane loading on the vibrations of the fully symmetric mechanical systems via dynamic simulation and generalized differential quadrature framework

Honeycomb structures are one type of structure that has the geometry of a honeycomb to allow the minimization of the amount of used material to reach minimal material cost and minimal weight. In this regard, this article deals with the frequency analysis of imperfect honeycomb core sandwich disk with multi-scale hybrid nanocomposite (MHC) face sheets. The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the composite layers. By employing Hamilton’s principle, the governing equations of the structure are derived and solved with the aid of the generalized differential quadrature method. Afterward, a parametric study is carried out to investigate the effects of the thickness to length ratio of the honeycomb core, honeycomb core thickness to inner radius ratio, value fraction of carbon fibers, radius ration of the disk, the angle of honeycomb network, the weight fraction of CNTs, and tensile and compressive in-plane force on the frequency of the sandwich disk with honeycomb core and MHC. The results show that the critical fiber angle is $$\theta_{{\text{f}}} /\pi =$$ 0.5 for C–C and C–S boundary conditions. Another consequence is that when the structure is fixed with S–S boundary conditions, for $$p =$$ 500 and $$p = 1000$$ , as well as the critical dimensionless angle for fibers is 0.5, there are two more range for critical fiber angle in which they are $$0.275 \le \theta_{{\text{f}}} /\pi \le 0.375$$ and $$0.23 \le \theta_{{\text{f}}} /\pi \le 0.39$$ , respectively. Additionally, the range of the critical dimensionless angle for fibers increases by increasing the applied load. Some new results related to dynamic behavior of an MHC are also presented, which can serve as benchmark solutions for future investigations.

Vibrational responses of a MHC viscoelastic thick annular plate in thermal environment using GDQ method

In this article, frequency analysis of multi-sized hybrid nano-composites (MHC) disk (MHCD) resting on elastic media and located in an environment with gradually changed temperature feature is presented. Carbon fibers (CF) or carbon nanotubes (CNTs) in the macro or nano sizes respectively are responsible for reinforcing the matrix. For prediction of the efficiency of the properties MHCD’s modified Halpin-Tsai theory has been presented. The strain-displacement relation in multi-sized laminated disk’s dynamics through applying third-order-shear-deformation-theory is determined. The energy methods called Hamilton’s principle is applied for deriving the motion equations along with boundary conditions, which has ultimately been solved using generalized differential quadrature method. The deflection as the function of time can be solved by the fourth-order Runge-Kutta numerical method. At the final stage, the outcomes illustrate that patterns of FG, fibers’ various directions, the W CNT and VF factors, top surface’s applied temperature have considerable impact on the MHCD’s dynamics. Another important consequence is that MHC structure with FG-A and UD patterns have a similar effect on the dimensionless natural frequency of the GPLRC disk, while FG-X has the lowest stability and natural frequency. A useful suggestion is that increasing the value of the length to thickness ratio of MHC not only decreases the central deflection of the structure through time but also causes to decrease real-time domain changes for the MHC viscoelastic annular plate. Numerical results declare that viscoelastic disks fabricated from the hybrid nanocomposites can endure higher frequencies compared with those consisted of conventional composites.

Extremely large oscillation and nonlinear frequency of a multi-scale hybrid disk resting on nonlinear elastic foundation

Abstract This is a fundamental study on the nonlinear vibrations considering large amplitude in multi-sized hybrid Nano-composites (MHC) disk (MHCD) relying on nonlinear elastic media and located in an environment with gradually changed temperature feature. Carbon fibers (CF) or carbon nanotubes (CNTs) in the macro or nano sizes respectively are responsible for reinforcing the matrix. For prediction of the efficiency of the properties MHCD's modified Halpin-Tsai theory has been presented. The strain-displacement relation in multi-sized laminated disk's nonlinear dynamics through applying Von Karman nonlinear shell-theory and using third-order-shear-deformation-theory (TSDT) is determined. The energy methods called Hamilton's principle is applied for deriving the motion equations along with Boundary Conditions (BCs), which has ultimately been solved using the perturbation approach (PA) and generalized differential quadrature method (GDQM). At the final stage, the outcomes illustrate that patterns of FG, fibers' various directions, the WCNT and VF factors, top surface's applied temperature and temperature gradient have considerable impact on the MHCD's nonlinear dynamics. Another important consequence is that, the influences of the θ, WCNT and VF amounts on the disk's nonlinear vibrations may be taken into account at the larger amounts of the high deflection element and the negative axial load's impact on the structure's nonlinear dynamics is more extreme. A more general conclusion of this study is that for designing the MHCD should be more attention to the nonlinearity parameter.

Bionic innovation design of disc brake

Creative thinking is the key factor of the product innovation design, and Bionic interaction design is a completely new method to achieve the creative design. In order to increase the abrasion resistance and reduce the natural frequency of automobile disc brake, and then weaken the brake squeal, the brake is designed from bionic points. Firstly, the brake is modeled at four levels of the function, principle, behavior and structure to fully express the internal relationship of the product; similarly, the corresponding biological system is modeled with function, strategy, action and structure based on the HIM. Meanwhile, considering the synergistic effect of multiple organisms, a multi-level Cooperative Mapping Mechanism based on multi-biological principle is raised to design the brake scheme. Secondly, thermodynamic and modal analysis of the bionic brake scheme is done. Finally, the bionic structure is parameterized designed based on numerical simulation to verify the feasibility and effectiveness of the proposed method.

Effect of turbine rotor disc vibration on hot gas ingestion and rotor-stator cavity flow

Gas ingestion numerical model and rotor-stator (RS) cavity model with rotor vibration are proposed to investigate the effect of rotor disc vibration on the flow characteristics in the RS cavity and gas ingestion. Results show that the sealing effectiveness at the rim seal clearance is increased due to the rotor disc vibration, and the amplitudes of the pressure fluctuation and the radial velocity of the gas ingestion flow at rim seal clearance are reduced. The speed of the Kelvin-Helmholtz vortex is approximately 82.28% of that without rotor vibration. Numerical results reveal that the effect of the rotor vibration on the RS cavity flow covers the whole cavity, the unsteady flow at the low radius region in RS cavity is caused by the vibration rotor disc. The frequency of the pressure oscillation at the low radius region is approximately equal to the vibration frequency of the rotor disc as the periodic variation of the tip clearance shape in the horizontal intake section of sealing air and the induced periodic mass flow rate of inlet sealing air. The flow characteristics in RS cavity are together determined by the rotor vibration parameters and the Kelvin-Helmholtz vortices in rim seal region.

Fast Data-Obtaining Algorithm for Data Assimilation with Large Data Set

Data assimilation is an analysis technique which combines observations and the numerical results from theoretical models to deduce more realistic and accurate data. It is widely used in investigations of the atmosphere, ocean and land surface. Due to the complicated data structure of the inputs from dynamical models and the increase of the amount of model data, the parallelization of data assimilation suffers from high overhead on file reading and data communication. In this paper, we propose a flexible parallel data access approach for reading a large number of data from disks firstly. Using this approach, the data access conflict is avoided successfully, and the frequency of disk addressing operations is also decreased significantly. Next, we design a communication-avoiding strategy to reduce the communication volume at the cost of some additional computations. Furthermore, we present a “pipe-flow” scheme for data exchange to conduct conflict-free message passing. Consequently, a fast data-obtaining algorithm is developed for the data assimilation. Our experiments show that the fast data-obtaining algorithm gains a performance of $$5\times $$ speedup compared with the baseline, which is excellent at data-obtaining for the parallel data assimilation. Due to the reduction of disk addressing operations, the new approach achieves $$6\times $$ speedup on average for the file reading process. Since a large amount of data movement can be avoided, the new approach achieves $$2.7\times $$ speedup on average for the communication between processors.

Tidal disruption event discs around supermassive black holes: disc warp and inclination evolution

ABSTRACT After the tidal disruption event (TDE) of a star around a supermassive black hole (SMBH), the bound stellar debris rapidly forms an accretion disc. If the accretion disc is not aligned with the spinning SMBH’s equatorial plane, the disc will be driven into Lense–Thirring precession around the SMBH’s spin axis, possibly affecting the TDE’s light curve. We carry out an eigenmode analysis of such a disc to understand how the disc’s warp structure, precession, and inclination evolution are influenced by the disc’s and SMBH’s properties. We find an oscillatory warp may develop as a result of strong non-Keplarian motion near the SMBH. The global disc precession frequency matches the Lense–Thirring precession frequency of a rigid disc around a spinning black hole within a factor of a few when the disc’s accretion rate is high, but deviates significantly at low accretion rates. Viscosity aligns the disc with the SMBH’s equatorial plane over time-scales of days to years, depending on the disc’s accretion rate, viscosity, and SMBH’s mass. We also examine the effect of fallback material on the warp evolution of TDE discs, and find that the fallback torque aligns the TDE disc with the SMBH’s equatorial plane in a few to tens of days for the parameter space investigated. Our results place constraints on models of TDE emission which rely on the changing disc orientation with respect to the line of sight to explain observations.