Convection Of Water Research Articles

Linear stability of Rayleigh-Bénard-Poiseuille flow of water near 4°C in a channel bounded by slip walls

The onset of mixed convection of cold water in a horizontal channel is studied using linear stability analysis. The two walls of the channel are modeled using slip conditions and are maintained at different constant temperatures. A model with a parabolic relationship is used to predict the variation of density with temperature in the range around its maximum density. The finite difference method is used to solve numerically the linearized equations, and the critical eigenvalue is obtained using the iterative Newton-Raphson method. The effects of the dimensionless temperature ratio γ and the slip parameter Ω on the onset of thermal instabilities are studied. The obtained results showed that these two parameters induced modifications in the critical Rayleigh number and the corresponding critical wavenumber. The results also indicated that beyond a certain value of dimensionless temperature ratio the slip parameter of the upper wall no longer influences the critical threshold for the onset of mixed convection.

Effects of wellbore and skin zone on co-seismic water level Responses: A numerical study

This study investigates the impacts of wellbore and skin effects on co-seismic water level changes. A numerical model has been developed to integrate hydraulic and geomechanically relevant elements, including the wellbore, aquifer system itself and the skin zone. In the model, Darcy flow and Navier-Stokes flow are coupled to simulate processes in the aquifer and wellbore consistently, incorporating two-phase flow of water and gas in the wellbore. The findings demonstrate the influence of wellbore and skin effects on co-seismic well water oscillation, especially during high-frequency seismic perturbations. The predominant wellbore effects arise from storage effect, friction, and water convection in well screen and casing. Positive skin decreases the oscillation amplitude and augments the phase shift, whereas negative skin displays a reversed effect. The effects of wellbore and skin zone may be negligible for co-seismic step changes in well water levels except the obstructive effect of an ultra-low permeability skin zone that may prevent water flow into or out of the wellbore. This model contributes to the understanding of underlying mechanisms affecting seismically induced water level changes by incorporating process-based water flow dynamics and providing an improved framework for their analysis and prediction.

Influence of Self-Heating on Landfill Leachate Migration

The hydrodynamic processes of landfill leachate migration in the base of a solid waste landfill can have a critical impact on the natural environment. In the case of improper operation of municipal solid waste placement facilities, highly contaminated leachate may penetrate into groundwater and subsequently into surface water. This work addresses fundamental issues of multicomponent fluid propagation in a multilayer porous medium, taking into account temperature inhomogeneities caused by waste decomposition with heat release. The regimes of diffusion and convection of leachate water penetrating into soil layers in the base of municipal solid waste facilities are numerically studied. Archival data from a set of field and laboratory measurements in the area of the operating landfill are used to model the features of pollutant propagation and determine migration parameters. The process of pollutant propagation and migration is described by quantitative values of dry residue content in leachate. Factors that have a significant impact on the migration of leachate are considered. The main ones are convective transfer, diffusion, and properties of the geological composition of the landfill base, which are taken into account in the mathematical formulation of the problem. The calculations show that leachate self-heating can substantially intensify leachate filtration and has to be taken into account in the assessment of leachate migration rate.

Numerical simulation of strengthening/deterioration and damage development of cementitious materials under sulfate attack environment

Cementitious materials exposed to sulfate environments often suffer from the combined effects of external sulfate attack and dry wet cycling. In order to predict the long-term performance of cement-based materials in sulfur rich environments, this paper aims to establish a numerical model that can reasonably characterize the degradation process of cementitious materials in sulfate environments. Using this model, we can address durability problems common to cementitious materials in real sulphate environments, such as determining the degree of corrosion, predicting the durability life of materials, and calculating the time to failure. The model consists of three parts: transportation, chemical reactions, and material damage. We establish the degradation model for cement-based materials in sulfate environments by considering ion diffusion, water convection, chemical reactions, accumulation of corrosion products, and the development of material strengthening/degradation. Compared with existing sulfate corrosion models, this model not only considers ettringite, but also takes into account the volume changes of gypsum formation, calcium leaching, and salt crystallization precipitation, which can more reasonably simulate the sulfate corrosion process in real environments. The model can reasonably simulate the distribution pattern of ion concentration, hydration products and corrosion products in the cementitious material, and on this basis calculate the porosity of the cementitious material. In order to make the simulation results more applicable to experimental and non-destructive testing results, the model uses easily obtainable relative dynamic elastic modulus to evaluate the degree of material strengthening/degradation and predict the durability life of the material.

Giant polygonal anhydrite ridges in the Southern Permian Basin

Giant polygonal anhydrite ridges with diameters of 2−4 km have been identified in the NE margin of the Southern Permian Basin in Poland. The primary ridges reach heights of 80−120 m, and secondary ridges, <40 m in height, subdivide them into smaller cells ∼1 km in diameter. The ridges were up to ∼40% higher before the alteration of gypsum to anhydrite. Both seismic and gravity surveys indicate the presence of similar structures over an area of thousands of square kilometers. Two alternative hypotheses, gypsum diapirism and free water convection, are proposed to explain their formation.

Modelling the effect of free convection on permafrost melting rates in frozen rock clefts

Abstract. This research develops a conceptual model of a karst system subject to mountain permafrost. The transient thermal response of a frozen rock cleft after the rise in the atmospheric temperature above the melting temperature of water is investigated using numerical simulations. Free convection in liquid water (i.e. buoyancy-driven flow) is considered. The density increase in water from 0 to 4 °C causes warmer meltwater to flow downwards and colder upwards, resulting in significant enhancement of the heat transferred from the ground surface to the melting front. Free convection increases the melting rate by approximately an order of magnitude compared to a model based on thermal conduction in stagnant water. The model outcomes are compared qualitatively with field data from the Monlesi ice cave (Switzerland) and confirm the agreement between real-world observations and the proposed model when free convection is considered.

Convective Water Vapor Energy Ablation (Rezum®) Versus Prostatic Urethral Lift (Urolift®): A 2-Year Prospective Study.

Introduction: To compare the clinical outcomes and complication rates of convective water vapor energy ablation (Rezum®) and prostatic urethral lift (Urolift®). To identify predictive factors for treatment failures in both treatments. Materials & Methods: Prospective clinico-epidemiological data of patients who underwent Urolift® or Rezum® in a single institution for benign prostatic hyperplasia (BPH) was collected. The choice of intervention depended on the preference of the patients after patient-centric discussions. Results: From October 2019 to October 2022, 86 patients underwent Rezum®, and 62 patients underwent Urolift®. Rezum® involved a longer indwelling catheter duration (12.38 ± 5.548 vs 1.39 ± 3.010 days, p < 0.001) compared with Urolift®. Rezum® was associated with more complications compared with Urolift® (36 [41.9%] vs 10 [16.1%] cases, p < 0.001). Rezum® had more cases of hematuria (17 [19.8%] vs 4 [6.5%] cases [p = 0.022]) and urinary tract infections (27 [31.4%] vs 3 [4.8%] cases, p < 0.001) compared with Urolift®. There were no significant differences in Clavien-Dindo Grade 3-5 complications between the interventions. Urolift® was associated with higher reoperation rates (5 [8.1%] vs 0 [0%] cases, p = 0.010) compared Rezum®. Rezum® had higher anticholinergic usage rates compared with Urolift® post-operation (22 [25.6%] vs 8 [12.9%] cases, p = 0.024). Both interventions showed improvement in the International Prostate Symptom Score (IPSS), quality of life score, and peak velocity flow over the 2 years with no significant difference between the two. Based on receiver operating characteristic curve, preoperation IPSS ≥16 had 95.7% sensitivity and 38.4% specificity to predict the probability of treatment failures after the interventions. Conclusions: There was no difference in clinical outcomes of patients who underwent Rezum® and Urolift®. However, patients who had undergone Rezum® faced more minor complications and more required anti-cholinergic medications. Lastly, physicians should note that patients with IPSS ≥16 would unlikely benefit from either intervention.

High-performance solar water purification enabled by controlled water convection in integrated porous aerogel multistage distiller

The employment of solar multistage distillers possessing thermal localization and energy cycle properties for saltwater desalination exhibits significant potential in fulfilling the increasing worldwide need for freshwater. In order to prevent salt crystallization on evaporators, most evaporators, however, excessively boost brine exchanging in distiller while ignoring heat loss during water convection. Here, we introduce an interesting porous aerogel-based multistage distiller (PAMS) that effectively suppresses heat loss during saltwater exchanging by controlling the water absorption rate through pore structure devising. This allows us to optimize the balance between evaporation, water transport, and salt-crystallization resistance. Finally, PAMS can reach a remarkable evaporation rate of 5.93 kg m−2h−1 and a high water-collection rate of 4.03 kg m−2h−1 under one solar irradiation thanks to the adjustable balance. Besides, PAMS exhibits impressive long-term stable antibacterial properties, which enhances the anti-biofouling and increases its reliability as a source of freshwater for ocean farm.

Effective Dissolution of a Gaseous Odorant in Liquid Using Gas Flow

AbstractOlfactory receptors are known for their high specificity, sensitivity, and nanometer‐sized sensing element, making them ideal for in situ odorant sensor applications. However, one of the major limitations of these sensors is the requirement for an aqueous environment to maintain their function, while most odorants are poorly soluble in water. To address this issue, a microfluidic device consisting of a gas‐flow channel and a microwell is proposed that enables the effective dissolution of a gaseous odorant in an aqueous solution. Computational simulations are used to design the gas‐flow channel and the well, and the performance of the odorant dissolution is verified using the fabricated device. This study considers that convection in water induced by the gas flow enhances the dissolution of a gaseous odorant. The feasibility of the device is demonstrated for on‐site detection of a gaseous odorant. This approach facilitates the development of highly responsive and portable sensors utilizing olfactory receptors, offering a promising solution to the limitations of current odorant sensors.

Thermo-adaptive interfacial solar evaporation enhanced by dynamic water gating

Solar-driven evaporation offers a sustainable solution for water purification, but efficiency losses due to heat dissipation and fouling limit its scalability. Herein, we present a bilayer-structured solar evaporator (SDWE) with dynamic fluidic flow mechanism, designed to ensure a thin water supply and self-cleaning capability. The porous polydopamine (PDA) layer on a nickel skeleton provides photothermal functionality and water microchannels, while the thermo-responsive sporopollenin layer on the bottom acts as a switchable water gate. Using confocal laser microscopy and micro-CT, we demonstrate that this unique structure ensures a steady supply of thin water layers, enhancing evaporation by minimizing latent heat at high temperatures. Additionally, the system initiates a self-cleaning process through bulk water convection when temperature drops due to salt accumulation, thus maintaining increased evaporation efficiency. Therefore, the optimized p-SDWE sample achieved a high evaporation rate of 3.58 kg m−2 h−1 using 93.9% solar energy from 1 sun irradiation, and produces 18–22 liters of purified water per square meter of SDWE per day from brine water. This dynamic water transport mechanism surpasses traditional day-night cycles, offering inherent thermal adaptability for continuous, high-efficiency evaporation.

Enhancing sludge hot-pressing drying by sawdust: Sensitivity analysis of heat and mass transfer physical properties of sludge, process performance, and kinetics

Hot-pressing drying shows promise in sludge treatment. Optimization often focuses on temperature and external load. However, the impact is restricted by sludge inherent properties, which can be changed by sludge conditioning. Due to coupling effects, altering individual sludge properties is difficult. Key sludge properties that significantly affect heat and mass transfer remain unclear, hampering identification of specific conditioning techniques. To address this gap, the effects of sludge specific heat, thermal conductivity, water activity, moisture diffusivity, and moisture permeability on drying performance were explored using sensitivity analysis. Sawdust conditioning and kinetics were employed to improve drying performance, validate sensitivity analysis findings, and elucidate drying mechanisms. Sensitivity analysis revealed that liquid water permeability significantly positively influenced drying performance by enhancing liquid water convection. Sawdust conditioning and kinetics demonstrated that adding 20 % sawdust increased drying flux from 31 to 62 kgwater·m⁻²·h⁻¹. The drying process included warm-up and constant rate, the first falling rate, and the second falling rate periods. Enhanced moisture transfer was dominated by breakthrough of interfacial gas film, transformation from liquid water diffusion to convection, and facilitated water vapor diffusion, respectively. Hence, this study provided novel insights, strategies, and direction of guidance for revealing sludge drying mechanisms and improving drying performance.

Benign Prostatic Hyperplasia Surgery: A Snapshot of Trends, Costs, and Surgical Retreatment Rates in the USA

BackgroundAn increasing number of novel surgical treatments (NSTs) for benign prostatic hyperplasia (BPH) have been proposed over time to achieve similar functional outcomes to, but better perioperative and sexual outcomes than traditional procedures. ObjectiveTo assess the trends in the utilization and costs of BPH surgical procedures over the past decade, and to analyze the need for surgical retreatment after each procedure. Design, setting, and participantsA retrospective observational population-based analysis was conducted using the PearlDiver Mariner (PearlDiver Technologies, Colorado Springs, CO, USA) database, including all-payer nationally available claims records collected from 2011 to 2022. Outcome measurements and statistical analysisThe number and type of BPH surgical procedures per year, costs associated with each BPH surgical treatment, incidence of BPH surgical retreatment rate, and time to BPH surgical retreatment were assessed. Negative binomial regression and Cochran-Armitage test were used for the temporal trend analysis. A multivariable logistic regression analysis evaluated the predictors of BPH surgical retreatment. Results and limitationsIn the study period, 274 808 patients received surgical treatment for BPH. The most common procedure was transurethral resection of the prostate (TURP; 71.7%). The overall utilization of BPH surgical treatment increased over the study period. Traditional surgery remained most performed for the entire period (87.8%), but a statistically significantly rising trend of NSTs was recorded. The mean reimbursements paid per procedure was 1.43 times higher (p < 0.001) for NSTs than for traditional procedures. The surgical retreatment rate was 9.4%. The mean time to surgical retreatment was 25.3 mo, with 85.5% of cases re-treated within 5 yr. At the multivariable analysis, transurethral incision of the prostate, photoselective vaporization of the prostate, prostatic urethral lift, convective water vapor energy, and prostatic artery embolization had a significantly greater likelihood of surgical retreatment than TURP. Holmium/thulium laser enucleation of the prostate (HoLEP/ThuLEP), open simple prostatectomy (SP), and laparoscopic/robot-assisted SP were associated with a lower probability of resurgery than TURP, but a similar probability between these procedures. Retrospective design and a lack of relevant clinical data were the main limitations. ConclusionsOver the past decade, there has been a progressive increase in the adoption of NSTs. The rate of surgical retreatment appears <10%, with patients undergoing SP and HoLEP/ThuLEP experiencing a statistically significantly lower probability of surgical retreatment. Patient summaryWe investigated the trends, costs, and surgical retreatments of benign prostatic hyperplasia surgery. Transurethral resection of the prostate remains the most common procedure. Novel surgical treatments are associated with an upward trend, despite appearing more expensive overall. Retreatment is necessary in <10% of patients and generally within 5 yr.

Influence of Two-Frequency Rotational Modulation on the Dynamics of the Rayleigh–Bénard Convection in Water-Based Nanoliquids with Either AA7072 or AA7075 Nanoparticles

The effect of time-periodic two-frequency rotation modulation on Rayleigh–Bénard convection in water with either AA7072 or AA7075 nanoparticles is investigated. The single-phase description of the Khanafer–Vafai–Lightstone model is used for modeling the nanoliquids. An asymptotic expansion procedure is adopted in the case of the linear stability to obtain the correction (due to modulation) to the Rayleigh number at marginal stability of unmodulated convection. A nonlinear regime of convection is considered with a nonautonomous generalized Lorenz model as the governing equation. The method of multiscales is then employed to obtain the coupled nonautonomous Ginzburg–Landau equations with cubic nonlinearity from the Lorenz model. These equations are presented in the phase-amplitude form and the amplitude is used to quantify the heat transport. The modulation amplitude is considered to be small (of order less than unity) and moderate frequencies of modulation are considered. We found that there is a threshold frequency beyond which the system behavior reverses. At frequencies below the threshold, the mean Nusselt number increases with an increase in the amplitude of modulation while an opposite influence is seen for values above the threshold. Such a behavior is a consequence of what is analogously seen in the case of the critical Rayleigh number. The influence of two-frequency modulation is more pronounced on the results of the linear and nonlinear regimes compared to that of the single-frequency one. The heat transport is enhanced due to the presence of dilute concentration of suspended nanoparticles (either AA7072 or AA7075 nanoalloys) in water. The influence of nanoparticles is to modify the threshold values generating chaos but it does not qualitatively alter the dynamical behavior of the system. The plots of Lyapunov exponents reveal that there is no possibility of hyper-chaos in the generalized Lorenz model when there is a rotational modulation.

Minimally-Invasive Surgical Techniques (MIST): Shedding Light on the Mist

As life expectancy increases and there is growing demand for BPH treatments, innovative technologies have been developed, allowing for swift recovery, symptom relief, low complication rates, and the possibility of performing procedures on an outpatient basis, often under local anaesthesia. This review aims to describe the outcomes of newly developed minimally-invasive surgical therapies (MIST) for BPH treatment in terms of functional voiding parameters and sexual function. These therapies are categorized into primarily ablative (Aquablation [Aquabeam]), non-ablative (Prostatic Urethral Lift (PUL, Urolift), temporary implantable devices [iTind]), and secondarily ablative procedures (convective water vapor ablation, Rezum, Prostate Artery Embolization [PAE]). All MIST technologies have advanced the medical care of patients with BPH while preserving ejaculation. However, there is a shortage of long-term data specifically addressing re-intervention rates and the preservation of functional voiding parameters. Although there is promising data from regulatory trials and randomized studies, all MIST therapies are potentially associated with severe complications. Patients considering such methods must be thoroughly informed about their inferiority compared with established transurethral procedures like TUR-P and enucleation.

Predicting the risk of failed trial without catheter following Rezum™ therapy.

Convective water vapor thermal therapy or "Rezum™" treatment for lower urinary tract symptoms in men with benign prostate hypertrophy require postoperative catheterization to avoid acute urinary retention. Unsuccessful catheter removal is still unpredictable. We, therefore, aimed to identify the risk factors of failed initial trial without catheter (TWOC) after Rezum™ therapy inside a large cohort of patients. A retrospective study was conducted on patients who underwent Rezum™ therapy by three referent urologists across two academic hospitals between January 2022 and January 2023. A Foley catheter was systematically placed after therapy for 7days in all patients before TWOC. Patients characteristics [age, imagery, maximum urinary flow rate (Qmax), postvoid residual (PVR)], and treatment outcomes (International Prostate Symptom Score (IPSS), quality of life (QoL), adverse events) were analyzed at baseline and 3months from procedure. Failed initial TWOC was defined as the incapacity to pass urine or measured PVR > 300mL. After univariate selection, the risk factors for TWOC failure were identified using multivariate logistic regression analysis. 216 patients qualified for analysis with 23 (10.6%) failing the first TWOC after 7days of catheterization. After multivariate logistic regression, only preoperative PVR predicted TWOC failure (OR 1.01; p = 0.007). The cut-off of preoperative PVR increasing this risk was 120mL (p = 0, 02). Over 10% of men undergoing Rezum™ therapy for LUTS/BPH will experience TWOC failure and AUR after 7days of catheterization. Preoperative PVR seems to be the only independent risk factor of unsuccessful catheter removal.

Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring

Deep oil and gas reservoirs are under high-temperature conditions, but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability, resulting in distorted resource assessments. The development of in situ temperature-preserved coring (ITP-Coring) technology for deep reservoir rock is urgent, and thermal insulation materials are key. Therefore, hollow glass microsphere/epoxy resin thermal insulation materials (HGM/EP materials) were proposed as thermal insulation materials. The materials properties under coupled high-temperature and high-pressure (HTHP) conditions were tested. The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased; additionally, increasing temperature accelerated the process. High temperatures directly caused the thermal conductivity of the materials to increase; additionally, the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity. High temperatures weakened the matrix, and high pressures destroyed the HGM, which resulted in a decrease in the tensile mechanical properties of the materials. The materials entered the high elastic state at 150 °C, and the mechanical properties were weakened more obviously, while the pressure led to a significant effect when the water absorption was above 10%. Meanwhile, the tensile strength/strain were 13.62 MPa/1.3% and 6.09 MPa/0.86% at 100 °C and 100 MPa, respectively, which meet the application requirements of the self-designed coring device. Finally, K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100 °C and 100 MPa. To further improve the materials properties, the interface layer and EP matrix should be optimized. The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.

Thermal performance of forced convection of water- NEPCM nanofluid over a semi-cylinder heat source

1) BackgroundPhase change materials (PCMs) have been used statically, which has caused the use of these materials to face challenges. Encapsulating PCMs and combining them with the base fluid can significantly solve the problem of using PCMs in BTM systems. In the present study, based on computational fluid dynamics, forced convection heat transfer of nano-encapsulated phase change materials (NEPCM) in a BTM system are simulated. The main aim of the present research is to reduce the temperature at the surface of the hot cylinder. 2) MethodsIn this research, we simulated lithium battery thermal management systems in both steady and transient states. The effects of using NEPCM particles to water were investigated. Modeling is implemented using the finite volume method and the PIMPLE and SIMPLE algorithms in OpenFoam. Furthermore, the effects of battery heat flux, Reynolds number, and the presence of nanoparticles (NPs) were analyzed. We intend to evaluate the optimal state of the system by studying the mentioned parameters. 3) Significant FindingsOur study shows that adding 3.5% NEPCM to water can reduce the length of the vortex by 22% and in unsteady-state simulation, it is observed that the presence of NEPCM particles in water reduces battery temperature up to 0.66 K.

Investigation of the chloride ion transport mechanism in unsaturated concrete considering the nonlinear seepage effect

In this paper, the mechanism of chloride ion transport in unsaturated concrete considering the nonlinear seepage effect is investigated by indoor experiments and analytical modelling. The concrete sheet imbibition test is used to reveal the nonlinear characters of seepage including water convection and moisture capillary within the unsaturated concrete in case of various water-binder ratios. For modelling purpose, an exponential function is introduced to mathematically depict the nonlinear relation between the specific discharge and hydraulic gradient during both water convection and moisture capillary processes. Based on such nonlinear seepage models, new mathematical models are proposed for the problem of chloride invasion within the reinforced concrete structure. The solution for the mathematical model of chloride transport is resolved by Laplace transform and finite difference method, of which acceptability is verified by the comparison with the results from chloride ion invasion test. The result indicates that, compared with linear seepage law, the use of the proposed nonlinear seepage solution is preferred to depict the saturation-relative humidity curves from concrete sheet imbibition test. The consideration of nonlinear seepage can result in a slower chloride transport rate, which further makes a later flow start-up time and a smaller free chloride iron concentration within the concrete. Such effect can be enhanced with the increase of nonlinear flow degree. The paper provides an effective solution to evaluate the chloride invasion within the unsaturated concrete.

Heat transfer characteristics of thermo‐diffusion (Soret) and diffusion‐thermo (Dufour) effects in a square cavity containing a non‐Darcy porous medium

AbstractThe impact of the double‐diffusive natural convection of water in a square enclosure with diffusion‐thermo and thermo‐diffusion around the non‐Darcy porous medium is studied numerically. The top and bottom side walls of the cavity are maintained at constant temperatures, while the vertical left and right walls are considered to be cold. Water is considered the working fluid. The resulting nondimensional partial differential equation is solved by the Marker and Cell (MAC) method by using a staggered grid system. The Dufour and Soret effects processes will be a significantly essential role in the double‐diffusive velocity flow processes. For different values of the relevant parameters, the fluid flow velocity, temperature, and concentration are presented for various Rayleigh numbers, Prandtl numbers, non‐Darcy, thermo‐diffusion, and diffusion‐thermo. The streamlines, isotherms, and iso‐concentration contours are obtained using the MATLAB software. Finally, it is observed that the Nusselt numbers increased with non‐Darcy, thermo‐diffusion, and Rayleigh numbers and decreased with diffusion‐thermo effects.

Microstructure-Driven Self-Transport and Convection of Water on Membrane Surface for Ultra-Fast, Highly Sensitive, Low-Cost Lateral-Flow Assays.

Lateral-flow assay (LFA) is one of the most commonly used detection technologies, in which the chromatographic membranes are currently used as the lateral-flow membrane (e.g., nitrocellulose membrane, NC Mem). However, several disadvantages of existing chromatographic membranes limit the performance of LFA, including relatively low flow velocity of sample solution and relatively more residuals of sample on membrane, which increase detection time and detection noise. Herein, a surface structure membrane (SS Mem) is proposed, which enables fast self-transport of water with a convection manner and realizes low residuals of sample on membrane surface after the flow. On SS Mem, the flow velocity of water is 7.1-fold higher, and the residuals of sample are decreased by 60-67%, comparing those in NC Mem. SS Mem is used as lateral-flow membrane to prepare lateral-flow strips of nanogold LFA and fluorescence LFA for rapid detection of SARS CoV-2 nucleocapsid protein. These LFAs require 210 s per detection, with limits of detection of 3.98 pgmL-1 and 53.3 fgmL-1, sensitivity of 96.5%, and specificity of 90%. The results suggest that SS Mem enables ultrafast, highly sensitive lateral-flow immunoassays and shows great potential as a new type of lateral-flow membrane to broaden the application of LFA.