Disturbed Layer Research Articles

Identification and characterisation of Late Neolithic (3600–2150 Cal. BC) living floors in a temperate environment: Case studies from the southern Paris Basin

Late Neolithic living floors in the southern Paris Basin are still not completely understood. In settlement contexts, the architecture and the organisation of activity areas are quite difficult to characterize and reconstruct. Only a few house plans are known. However, many thinly stratified sites with artefact spreads could represent preserved living floors. The aim of this paper is to investigate the formation processes of this type of site through geoarchaeological study (soil micromorphology) of three sites (Gas, Sours and Pussigny), located in different geographic contexts. In particular, discussion centres on whether these are disturbed layers or well or partially preserved living floors. Using micromorphological analysis we were able to identify several constructed micro-facies (invert, backfill and screed) and functional micro-facies (trampled occupation surfaces inside or outside buildings). The microstratigraphic organisation of pedo-sedimentary sequences could be representative of different types of living floor: constructed floors inside cob buildings, living floors just outside buildings and yard floors. The results of this research confirm that the artefact spreads are the visible aspect of living floors. While for a long time the preservation of living floors was not considered because the conditions were regarded as unfavourable, this study actually demonstrates their possible preservation in different geomorphological and pedological contexts, as well as their informative potential. Moreover, the study shows that the artefact spreads reflect different spaces, depending on environmental conditions and human activities. In a context where data on Late Neolithic architecture in the south-western part of the Paris Basin is limited, these results confirm the presence of built structures on these sites and provide insights into the raw materials used for the construction of houses. Ultimately, the results contribute new knowledge and broaden the fields of research in geoarchaeology and the palaeo-ethnology of living floors.

Reduction in DC-Drift in LiNbO3-Based Electro-Optical Modulator

This study involves the results of research on short-term and long-term DC-drifts in electro-optical modulators based on annealed proton exchange waveguides in LiNbO3 crystals after wafer pre-annealing. The relaxation time of the DC-drift of the operating point for a short-term drift is measured in minutes, and for a long-term drift it is measured in hours and days. DC-drift was measured by applying bias voltage and changing crystal temperature. The obtained results show significant impact on the stability of operating point in EO-modulators after treatment of defective structure of the near-surface layer of a LiNbO3 crystal. Treatment of the disturbed near-surface layer of a LiNbO3 crystal results in the simultaneous reduction in short-term DC-drift and increase in operation stability of electro-optical modulators during long-term measurement of temperature by activation energy calculation.

The Influences of Local Glacitectonic Disturbance on Overconsolidated Clays for Upland Slope Stability Conditions: A Case Study

Reliability of equilibrium state evaluation about settlement slopes in the context of natural and human-made hazards is a complex issue. The geological structure of the vicinity of the upland slope in the urban environment of Warsaw is characterised by a significant spatial diversification of the layers. This is especially due to the glacitectonics in the Mio-Pliocene clays, which are located shallowly under the sandy tills’ formations. With substantial variability in the clay roof surface, point recognition by drilling is often insufficient. The use of electrical resistivity imaging (ERI) in the quasi-3D variant provides accurate images of the real ground conditions, which is crucial in optimal geotechnical design. In forecasting the behaviour of the slope, it is necessary to quantify the impact of spatially differentiated systems of disturbed layers on changes in the safety factor (SF), which corresponds to the observed landslide activity of the Warsaw Slope. This study concerns numerous calculation model analyses of the optional clay position in the context of slope stability conditions. A wide range of soil properties variability was taken into account, resulting from both lithogenesis and subsequent processes disintegrating the original soil structure. Regarding the geological conditions of the slip surface, the use of classical computational methods and numerical modelling (FEM) was considered for comparative purposes. The results indicated that local changes in equilibrium conditions were affected by the different morphology of the clay roof surface of the slope and the alternation in strength characteristics on the slip surfaces. The findings of the study contribute to sustainable spatial planning of near-slope regions.

CERAMIC STAMPS FROM VILINO (RASSADNOE) — IN PERIODIZATION AND CHRONOLOGY OF THE SITE (SOUTH-WESTERN CRIMEA)

This paper is devoted to the publication of amphora stamps discovered during excavation at the settlement of Vilino (Rassadnoe) in 2008—2014.
 During the research of the settlement the eastern border of the ancient estate and the main chronological framework of the settlement life were ascertained. The stone monumental structure was discovered in 2008. This is the cistern for collecting and storage of rainwater. In the Late Scythian time it was used as a burial structure (crypt).
 Ceramic stamps found at the site are represented by such centers as Sinopa, Chersonesos, Rhodes. Unfortunately not all of them were discovered in the cultural layers (in situ) and some were found in disturbed layers, at the surface or in the looter’s holes. Nevertheless, with a lesser or greater degree of probability, it’s possible to correlate them with the chronology of the settlement and periods of its life.
 On the excavated areas of the site four building periods (A—D) were observed — two Classic and two Late Scythian. The first period is associated with the time of activity of the Greek fortified estate (Chersonesos Сhora) from the last quarter of the 4th to the early 3rd century BC. In the second period, after a break, the population has come back to the settlement in the last quarter of the 3rd century BC. There was the period of recolonization during which the restructuring of the settlement has carried out. At the end of the first quarter of the 2nd century BC the life at the settlement was stopped. The next two periods correspond to the Late Scythian culture. However, the layers and building remains of the late 2nd century BC — 1st century AD was destroyed by plowing and looter’s holes. The upper horizon of the settlement contains the material from the 1st—3rd centuries AD.
 The stamps and other archaeological material are important chronological indicators of the archaeological site in the system of the Chora of Chersonesos and in the whole Western Crimea.

Field Performance and Rapid Repair Method of an Airfield Pavement under the Blast Load of Cluster Bomb Unit

This paper discusses a field test of airfield pavement under cluster bomb unit (CBU) blast load and a study of repair method upon the examination of the damage geometry. Cluster bomb unit blast load shows a similar level to that of a typically known air-to-ground munition, and the penetration depth was calculated using empirical formulae with terminal velocity during a free fall following an explosion and dispersion 20km above the ground. Based on the calculations, the field test was executed assuming a cluster bomb unit penetration depth of 33cm for concrete pavement surface. The concrete slab on the test site was casted in a circular shape at the field and then cured. This slab was an unreinforced concrete structure with a similar compressive strength and thickness as that of airfield pavement currently in use. The test reflected the cluster munition penetration depth of 33cm, and the concrete slab was drilled in the center and explosive with a weight resembling that of the cluster munition installed. As results of the blast test show a damage to the pavement expanded the crater to a depth of 78cm, down to the crushed stone layer and with a diameter of 30cm. The concrete fragmentation requiring removal was of about 156cm in radius on average. The 7 tensile cracks across the pavement were not so heavily damaged to require removal. Cutting and removing the crushed concrete slab with dimension of 1.8m × 1.8m, compacting the disturbed crushed stone layer and repairing the concrete slab section using ultra-rapid hardening concrete are reviewed the appropriate repair method based on the above results.

Conservation Treatment on the Bamboo Sunblind from the No. 1 Catchment Site in Baesanseongji, Busan

In the present study, safe management and value improvement of bamboo sunblind, which is an item of cultural heritage, were performed by adopting stable conservation treatment methods. The bamboo sunblind used in the present study was excavated from No. 1 catchment site in Baesanseongji, Busan. It was determined that the main material used to make the sunblind was bamboo, and herbal plants were used to weave the bamboo using lacquer as an adhesive agent. All contaminants and soil adhered to the sunblind was removed. Thereafter, the sunblind, which was recovered in the form of blocks, was washed separately after fixing it to a temporary plaster frame and to avoid the blocks from breaking during washing. Then, polyethylene glycol (PEG) impregnation was utilized for the reinforcement treatment. Based on the preliminary test results, the shape of the sunblind was fixed using a stainless-steel frame to prevent physical damage that may occur during the drying process. Thereafter, the bamboo sunblind was vacuum freeze-dried. PEG 20% (in ethyl alcohol) was applied as a surface treatment agent for stabilization the sunblind. After the surface treatment, the bamboo sunblind were joined together to fit the maximum width, and the rectangular shape of the sunblind was restored—as best as possible—while filling in the missing parts by maximizing the use of unknown members such as in the disturbed layers below bamboo sunblind surface. The conservation treatment was completed by fixing the bamboo sunblind into the fabricated frame.

Numerical simulation of the interaction of the disturbed boundary layer with an incident shock

Interaction of the disturbed supersonic boundary layer with an incident oblique shock wave is studied numerically with eddy-resolving numerical simulations. Eigenmodes of the linear stability theory are used to generate the inflow boundary layer disturbances. The evolution of unstable boundary-layer disturbances, effects of the incident shock on the disturbances, effects of the disturbances on the boundary layer separation, flow dynamics in the separation zone, and laminar-turbulent transition are studied.

Integrating Ground Penetrating Radar, Induced Polarization and Aerial Photograph to Analyze Land Subsidence in Borehole Mining Operation Area: A Case Study from South Bangka Island

The remaining alluvial tin reserves around large ex-mining area can be an opportunity to optimize the potential reserves using a small-scale mining system. One of the latest breakthroughs in the mining system for the remaining alluvial tin reserves on land is the borehole mining (BHM) method. However, mining operations using BHM have several environmental impacts especially related to its former holes. This study aims to identify the changes in geometry of the former holes both on the surface and below the surface through direct field observations and measurements using geophysical methods. The study site is in the large ex-mining area of Air Nudur Block in South Bangka Regency, Bangka Belitung Islands Province. The geophysical methods used to identify the changes in the geometry of the BHM holes are GPR (ground penetrating radar) and IP (induced polarization). The GPR method has high resolution subsurface visual capabilities at shallow depths and this method can distinguish between stable and unstable layers. The IP method is used to determine the overburden layer and the condition of the alluvial layer where some of it has become a hole. These two methods will mutually reinforce in interpreting the change in the geometry of the BHM holes. Changes in hole diameter and depth were measured directly in the field within 2 (two) months from the completion of mining operations using the BHM method followed by the periodic topographic measurements using UAV (unmanned aerial vehicle). The results of observations on changes in the elevation of the ground surface around the former BHM hole indicated that the land level subsided by about 1 m. Meanwhile, the results of GPR data processing showed changes in the hole geometry with the hummocky radargram pattern into chaotic. Interpretation of IP data processing shows resistivity values of 250 - 1700 ohm.m and chargeability of 15 - 25 ms in the disturbed alluvial layer around the former BHM holes.

атухание низкочастотных электромагнитных волн в нижней ионосфере земли под влиянием сильного локального возмущения в атмосфере.

The value and duration of attenuation of low frequency waves (1...10 kHz) in the presence of a strong local disturbance of the atmosphere have been estimated. Sources of significant local disturbances of the atmosphere are, for example, precipitation of energetic particles of radiation belts; electromagnetic pulses of lightning discharges; radiation of powerful low-frequency ground-based transmitters; invasion of large meteors. Strong local disturbances lead to an increase of ionization (concentration of free electrons) of the environment by several orders of magnitude in the region of space whose characteristic dimensions are comparable to the length of the wave (tens and hundreds of kilometers). As such a disturbance, we use the previously developed macroscopic model of an instantaneous, point release of a relatively large amount of energy in the atmosphere below the ionosphere. This model makes it possible to estimate the features of the propagation of low-frequency waves through the disturbed layer of the lower ionosphere by changing only two initial parameters: the disturbance energy and its initial height. It is shown that the attenuation value is almost independent of frequency and geo- and heliophysical conditions. For initial heights up to 50 km, the fading duration does not exceed ~ 2 min. With an increase of the initial altitude, the attenuation in the lower ionosphere becomes extremely large. However, for heights of 50 ... 70 km (depending on the value of energy), the horizontal size of the disturbance decreases significantly, which leads to a decrease in the fading time to tens of seconds for initial heights of more than 80 km.

Landslide vulnerability of the Debre Sina-Armania road section, Central Ethiopia: Insights from geophysical investigations

Geophysical investigations using 2D electrical imaging and magnetic methods have been conducted to study the landslide problem on the road located at Dokakit Kebele near Sar Amba Kidane Mhiret locality between Debre Sina and Armania towns in Central Ethiopia. From field observations, the landslide problem in the Debre Sina-Armania road section at Dokakit is due to a combination of factors, the most important of which are topography, the high degree of weathering, hydrology of the area, and human activities. Among these factors, human activities that include deforestation for housing, agricultural activities, search for building materials, and road construction are generally assumed to be the triggering factors for slope failure in the area. From the interpretation of the geophysical results, the near-surface geology of the study area is found to be composed of massive deposits of fragmented basalts and structurally disturbed layers together with expansive clay soils, which considerably contribute to the sliding problem. Another contributing factor to the subsurface instability is the high gradient slope in the area and the lack of vegetation/wooded tree cover. From the geophysical survey results, it has further been possible to map zones of weakness in the subsurface over which the geologic layers slide as well as their vertical and lateral extents. Areas of active sliding surfaces and extensive subsurface cracks, especially at the two ends of the profiles, were mapped. A combination of numerous weak zones, deep weathering conditions of the lithologic units, the action of rainfall, springs, and the high slope gradient of the study area were the contributing factors for this sliding problem. Remedial measures to stabilize a section of the affected area and construction of a detour road are proposed as mitigation measures for the road segment's recurrent and rather expensive failure over the locality.

EFFECTS OF DIFFERENT GEOMETRICAL STRUCTURES ON THE SOIL DISTURBANCES AND WORKING RESISTANCES OF VERY NARROW TINES APPLIED ON NATURAL GRASSLAND

Novel tillage tools with high working performance are desired in improving degraded natural grassland tillage system. This paper aimed to find the influence of various geometry structures of very narrow tines on related soil disturbance characteristics and tillage resistances. Four shank-type tillage tines with different cutting head shapes, and the test bench were designed and manufactured. Field experiments under different working depths were conducted. The working depth uniformity, soil over-turning rate, cross-section area of disturbed soil layer, and related forces were obtained, analysed, and compared. Results showed that, the working depth uniformities were above 70%, and soil overturning rates did not exceed 5%. Furrows with V-shaped cross-section were formed. The tine with an arc-shaped cutting edge (AT) obtained a lower draft force value, and the tine with chamfer structure (TTD) presented big differences on the draft force and soil disturbance compared to the tine with blunt cutting edge (TT). Both the draft force and the area of disturbed soil cross section had a good linear relationship with the working depth, and the specific draft force increased with the working depth increasing. Using a very narrow tine with chamfers to split and break the soil layer on the natural grassland without pulling or dragging the roots could be an appropriate tillage method applied for improving degraded natural grassland, but still need further surveys.

Simulation of the dynamic disturbance characteristics of the soft sediment in the Diexi ancient dammed lake, China

In an earlier study of the Diexi ancient dammed lake along the Minjiang River in Southwest China, 10 disturbed layers with envelope and flame structures were found in more than 240 m of lacustrine sediments. In this paper, the soft-sediment disturbances caused by earthquakes in the Diexi ancient dammed lake were studied based on field investigations and laboratory core observations. A two- to three-degree-of-freedom spring-type earthquake simulation vibration table was used to carry out disturbance tests on lacustrine sediments under different dynamic conditions. The results support the following conclusions: (1) The disturbance layers in the lacustrine sediments were caused by strong earthquakes in the region. (2) The characteristics of the disturbance layers are related to the seismic parameters and the degree of sediment consolidation. (3) The greater the earthquake intensity is, the greater the disturbance amplitude is; moreover, the lower the consolidation degree is, the greater the disturbance amplitude. (4) The simulation tests verify that the disturbance layers in the sediments of the Diexi ancient dammed lake correspond to strong earthquakes in the region. These results are valuable for ongoing palaeoseismic research in the region.

Comparison of DFN Modelled Microfracture Systems with Petrophysical Data in Excavation Damaged Zone

Physical and petrographic properties of drill core specimens were determined as a part of investigations into excavation damage in the dedicated study area in the ONKALO® research facility in Olkiluoto, Western Finland. Microfractures in 16 specimens from two drillholes were analysed and used as a basis for fractal geometry-based discrete fracture network (DFN) modelling. It was concluded that the difference in resistivity between pegmatoid granite (PGR) and veined gneiss (VGN) specimens of similar porosity was likely due to differences in the types of microfractures. This hypothesis was confirmed from microfracture analysis and simulation: fractures in gneiss were short and mostly in one preferred orientation, whereas the fractures in granite were longer and had two preferred orientations. This may be due to microstructure differences of the rock types or could suggests that gneiss and granite may suffer different types of excavation damage. No dependencies on depth from the excavated surface were observed in the geometric parameters of the microfractures. This suggests that the excavation damaged zone cannot be identified based on the changes in the parameters of the microfracture networks, and that the disturbed layer observed by geophysical methods may be caused by macro-scale fractures.

Efficient reduction of the consumption of fuel in road vehicles using aerodynamic behavior in CDF analysis

A consistent increment in global energy has direct effect on fuel costs. This along with the ecological issues brought about by the exhaust gases of vehicles is the principle motive behind the requirements to decrease fuel utilization of streets vehicles. Decreasing aerodynamic drag can prompt in decrease of fuel utilization leading to the reduction of environmental issues. Ongoing work in streamlined features has zeroed in on issues identified with compressible stream, disturbance, and limit layers and has gotten progressively computational in nature. Vortices are one of the numerous marvels related with the investigation of optimal design.

Epithelial loss of mitochondrial oxidative phosphorylation leads to disturbed enamel and impaired dentin matrix formation in postnatal developed mouse incisor

The formation of dentin and enamel matrix depends on reciprocal interactions between epithelial-mesenchymal cells. To assess the role of mitochondrial function in amelogenesis and dentinogenesis, we studied postnatal incisor development in K320E-TwinkleEpi mice. In these mice, a loss of mitochondrial DNA (mtDNA), followed by a severe defect in the oxidative phosphorylation system is induced specifically in Keratin 14 (K14+) expressing epithelial cells. Histochemical staining showed severe reduction of cytochrome c oxidase activity only in K14+ epithelial cells. In mutant incisors, H&E staining showed severe defects in the ameloblasts, in the epithelial cells of the stratum intermedium and the papillary cell layer, but also a disturbed odontoblast layer. The lack of amelogenin in the enamel matrix of K320E-TwinkleEpi mice indicated that defective ameloblasts are not able to form extracellular enamel matrix proteins. In comparison to control incisors, von Kossa staining showed enamel biomineralization defects and dentin matrix impairment. In mutant incisor, TUNEL staining and ultrastructural analyses revealed differentiation defects, while in hair follicle cells apoptosis is prevalent. We concluded that mitochondrial oxidative phosphorylation in epithelial cells of the developed incisor is required for Ca2+ homeostasis to regulate the formation of enamel matrix and induce the differentiation of ectomesenchymal cells into odontoblasts.

An analysis of global ionospheric disturbances and scintillations during the strong magnetic storm in September 2017

Severe space weather events, e.g., solar flares and magnetic storm, can cause significant disturbances to the global ionosphere. The radio frequency signals, such as wireless communications and global satellite navigation system (GNSS) signals, often experience strong scintillations when traveling through the disturbed ionosphere layer. On 6 September 2017, the sun emitted the largest solar flare classified X9.3 since the 24th solar activity week. It triggered the geomagnetic storm and ionospheric storm on September 8, causing severe disturbances and scintillations of ionospheric. In this work, we take this event as the objective to investigate the characteristics of the ionosphere disturbance. First, the temporal and spatial distributions of ionospheric total electron content (TEC) are analyzed using the ground-based IGS data. The change of TEC is highly correlated with that of the geomagnetic indices and the magnetic storm has the greatest impact on low latitudes. Then, a five-point moving average method is adopted to extract the spatial fluctuations based on post-processed electron density and TEC data from COSMIC and GRACE missions. We find they show different disturbance characteristics in spatial distribution. In addition, the GNSS amplitude scintillation index S4 which is available from the COSMIC satellite mission is used to characterize ionospheric scintillation during this event. Weak scintillation occurred in most parts of the world on September 8 2017, while moderate scintillation is mainly concentrated around 120° W and 100° E. Our study can provide a basis for better evaluating the impact of ionosphere disturbance changes on satellite communication and navigation in space weather events.

The effect of vortices structures on the flow-induced vibration of three flexible tandem cylinders

Flow-induced vibration (FIV) is a phenomenon oftentimes occurring in practical situations where flexible cylinders are immersed in an oncoming flow. Understanding the FIV characteristics in different vortex structures plays an important role in vibration control and utilization of engineering structures, such as offshore stacks and bladeless wind turbines. A detailed investigation on FIV of flexible tandem cylinders in the atmospheric boundary layer (ABL) under various vortex structures through setting strakes were conducted experimentally and numerically. The typical FIV responses and dynamic vortex evolutions at two specific spans, 1.4 and 3.2, were obtained in Ur∈[2, 35] to demonstrate the effect of different vortices. At the small span, FIV of tandem cylinders depends on the shear layers interaction, which behave as a uncircular bluff body with a pivot point near the downstream cylinder. Under the irregular small-scale vortices generated by the disturbed shear layer, the second instability of FIV of tandem cylinders at Ur≥20 can be excited. At the moderate span, the fully developed wake interference predominates. Among the effect of three different vortex structures, FIV of tandem cylinders cannot be promoted by steady vortices; clear FIV responses at Ur<10 with larger amplitudes can be observed in periodic oscillating vortices; FIV response of downstream cylinders at small reduced velocities decreases but another instability with divergent FIV will re-occur at Ur≥20 in irregular oncoming small-scale vortices. Finally, the vortices structures in different scales are assessed through the turbulence kinetic viscosity, and the instabilities of aerodynamic forces affected by the small-scale vortices are discussed.

Stress-strain behaviour as a factor constraining the processing conditions for low-stiffness brittle workpieces

These days, navigation items [1] that contain a gyroscope [2] as a part thereof widely use ceramic materials, glasses, and sitalls [3,4], which all have high isotropy; this is necessary in order to ensure high accuracy of operation of the items under review. A major element of a solid-state wave gyroscope (SWG) is a resonator—or, as it is often called, a sensing element—which has a rather difficult-to-manufacture geometry. High quality of the surface is achieved using various methods of blank processing, one of which is a method of layer-by-layer removal of the disturbed layer by repeating the machining and chemical treatment operations [5]. The second part of item finishing preparation is polishing, which can be done either with one tool or with two tools. Shear stresses that occur in a brittle blank can result in its destruction or initiate a crack, which decreases its fatigue strength. Therefore, appropriate assignment of processing conditions and monitoring of the stress-strain behaviour, in order to ensure the operability of the item at frequencies close to 7000 Hz, are vital challenges. The stress-strain behaviour of the item is reviewed at times when a processing tool is either on the inside or outside of the item being processed. The results obtained are presented; an effect of the tool position is analysed; recommendations on assigning the processing conditions are given.

Disturbance and resilience of aSphagnumpeatland in western Russia (Western Dvina Lakeland) during the last 300 years: A multiproxy, high-resolution study

This paper presents the results of multiproxy research (pollen, charcoal, plant macrofossil and testate amoebae) on the biogenic deposits core from Gorodetsky Moch, an ombrotrophic peatland in western Russia (Western Dvina Lakeland). We reconstructed the impact of disturbance on peatland development in the last 300 years by using chronology of the records based on14C and210Pb data set. The multiproxy reconstruction was compared with changes in the land cover using historical maps and Corona images, which provides a unique spatial analysis of past ecological and land-use changes. We aimed to determine the effect of local disturbances (drainage) and land-use changes (landscape openness) on the development of the peatland during the last 300 years. Our study suggests that human activity had a crucial impact on the development of the peatland in the last centuries. The analysis of testate amoebae and plant macrofossils revealed a clear disturbed layer in the second half of the 20th century CE. Most probably, the drainage of the peatland triggered changes in the community of testate amoebae and plants, thereby causing a functional shift in Sphagnum peatland ecosystem. The hydrological stress and vegetation composition shift led to the collapse of mixotrophic testate amoebae. However, the peatland showed strong resilience and recovered toward the end of the 20th century CE and the beginning of the 21st century CE, despite the lower water table. Our study shows an example of the peatland ecosystem that experienced a considerable stress but finally sustained the former function.

Mixing enhancement in a subsonic-supersonic shear layer with a cavity splitter plate

The development of more efficient ramjet engines has motivated the study of enhanced mixing in compressible shear layers. Cavity-mixer is a widely used passive flow control tool, but its mixing enhancement mechanisms in compressible subsonic-supersonic shear layers has yet to be comprehensively explored. In this work, a cavity-mixer is used to increase mixing in a subsonic-supersonic shear layer, and the underlying flow control mechanisms are examined. Parametric experiments were performed on a laboratory-scale blowdown wind tunnel and an extraction wind tunnel. Numerical simulations were performed in a large eddy simulation framework. Schlieren and nanoparticle-based planar laser scattering techniques were adopted for mixing flow visualization. It is found that the growth rate of the cavity (length-to-depth ratio of 5) disturbed shear layer is 31% higher than the benchmark configuration at convective Mach number of 0.49∼0.56. It is demonstrated that the compressibility and length-to-depth ratio affect the cavity-mixer performance. High convective Mach number suppresses the cavity disturbance and weakens its mixing enhancement efficiency. Cavity-mixer with a length-to-depth ratio of 3 shows the highest experimental and numerical growth rate, compared to 5 and 7 under a convective Mach number around 0.49. Large-scale coherent vortices are confirmed in the subsonic-supersonic mixing process. Cavity disturbance promotes the three-dimensional characteristics of the flow field, increases the vorticity of large coherent structures, and advances the K-H instability position of shear layer, which plays a key contribution to mixing enhancement.