scholarly journals A Mathematical Model for Swallowing of Concentrated Fluids in Oesophagus

2011 ◽  
Vol 8 (3-4) ◽  
pp. 309-321 ◽  
Author(s):  
S. K. Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Plug Flow ◽  
Flow Region ◽  
Mechanical Efficiency ◽  
Casson Fluid ◽  
Local Pressure ◽  
Integral Number ◽  
Tomato Puree ◽  
The Impact

This model investigates particularly the impact of an integral and a non-integral number of waves on the swallowing of food stuff such as jelly, tomato puree, soup, concentrated fruits juices and honey transported peristaltically through the oesophagus. The fluid is considered as a Casson fluid. Emphasis is on the study of the dependence of local pressure distribution on space and time. Mechanical efficiency, reflux limit and trapping are also discussed. The effect of Casson fluid vis-à-vis Newtonian fluid is investigated analytically and numerically too. The result is physically interpreted as that the oesophagus makes more efforts to swallow fluids with higher concentration. It is observed that the pressure is uniformly distributed when an integral number of waves is there in the oesophagus; but it is non-uniform when a non-integral number of waves is present therein. It is further observed that as the plug flow region widens, the pressure difference increases, which indicates that the averaged flow rate will reduce for a Casson fluid. It is also concluded that Casson fluids are more prone to reflux.

PERISTALTIC TRANSPORT OF A CASSON FLUID IN A FINITE CHANNEL: APPLICATION TO FLOWS OF CONCENTRATED FLUIDS IN OESOPHAGUS

2010 ◽  
Vol 03 (04) ◽  
pp. 453-472 ◽  
Author(s):  
S. K. PANDEY ◽  
DHARMENDRA TRIPATHI
Keyword(s):  
Pressure Distribution ◽  
Flow Rate ◽  
Plug Flow ◽  
Flow Region ◽  
Mechanical Efficiency ◽  
Casson Fluid ◽  
Food Bolus ◽  
High Concentration ◽  
Integral Number ◽  
Activated State

This model is targeted to study the swallowing of peristaltically driven food stuff such as jelly, tomato puree, soup, concentrated fruit juices and honey in the aboral direction confined to an oesophagus by modeling it as finite channel. Considering such highly concentrated fluids as Casson fluid in the fully stretched activated state, the dependence of pressure on space and time has been investigated for time averaged flow rate. Pressure distribution has been studied along the oesophageal length for an integral and also a non-integral number of waves at different time instants. Local wall shear stress and the role of yield stress have also been the areas of investigation. Mechanical efficiency of oesophageal pump during the Casson food transportation has been obtained. Reflux limit of perstaltically driven flow of Casson food bolus has also been discussed. The effect of Casson food bolus vis-à-vis Newtonian food bolus has been compared analytically, numerically and computationally from investigation point of view. It is observed that the pressure distribution is even and uneven respectively for the case of integral and non-integral number of waves. It is also concluded that it is not as easy to swallow Casson fluids (such as concentrated jelly, honey, soup, juice, etc.) as Newtonian fluids (such as water). As plug flow region widens, the pressure difference increases, indicating thereby that the averaged flow rate will be less for a Casson fluid. Physically, the oesophagus works more to swallow fluids with high concentration. It is also inferred that such fluids are more prone to reflux.

scholarly journals A Mathematical Model for the Flow of a Casson Fluid due to Metachronal Beating of Cilia in a Tube

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
A. M. Siddiqui ◽  
A. A. Farooq ◽  
M. A. Rana
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Pressure Rise ◽  
Cylindrical Tube ◽  
Casson Fluid ◽  
Volume Flow ◽  
System Of Nonlinear Equations ◽  
Dimensional System ◽  
Axial Pressure Gradient

A mathematical model is developed to study the transport mechanism of a Casson fluid flow inspired by the metachronal coordination between the beating cilia in a cylindrical tube. A two-dimensional system of nonlinear equations governing the flow problem is formulated by using axisymmetric cylindrical coordinates and then simplified by employing the long wavelength and low Reynolds number assumptions. Exact solutions are derived for the velocity components, the axial pressure gradient, and the stream function. However, the expressions for the pressure rise and the volume flow rate are evaluated numerically. The features of the flow characteristics such as pumping and trapping are illustrated and discussed with the help of graphs. It is observed that the volume flow rate is influenced significantly by the width of plug flow regionHpas well as the cilia length parameterε. The analysis is also applied and compared with the estimated value of the volume flow rate of epididymal fluid in the ductus efferentes of the human male reproductive tract.

scholarly journals Investigation of Hydraulic Performance Based on Response Surface Methodology for an Agricultural Chemigation Proportional Injector

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3155
Author(s):  
Pan Tang ◽  
Chao Chen ◽  
Hong Li
Keyword(s):  
Mathematical Model ◽  
Response Surface ◽  
Flow Rate ◽  
Hydraulic Performance ◽  
Differential Pressure ◽  
Impact Factors ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
The Impact ◽  
Injection Ratio

Injectors are key pieces of equipment for chemigation systems, and their hydraulic performance has a significant effect on chemigation systems and crops. In order to investigate the influence of different working parameters on hydraulic performance for a water-powered proportional injector (PI), three key parameters of inlet and injection flow rate were researched using a one-factor experimental design method. The regression equations between different factors and response variables were established through a response surface method based on one-factor experimental results. Lastly, a mathematical model of the actual injection ratio was established. Some experiments under different, randomly selected parameter combinations were carried out to verify the prediction precision of the mathematical mode. The results showed that the injection flow rate increased first within the differential pressure of 0.05 to 0.10 MPa and then tended towards stability with increasing differential pressure. The injection flow rate decreased by increasing the viscosity and the change in the injection flow rate was small enough when the viscosity was greater than 500 mPa·s. The impact factors, in order of significance, for inlet flow rate were differential pressure, viscosity of injection liquid and setting injection ratio. The impact factors, in order of significance, for injection flow rate were viscosity of injection liquid, setting injection ratio and differential pressure. The regressive model for predicting the actual injection ratio was validated using an experiment and the relative deviation between calculated value and tested value was less than 5.98%, which indicated that the mathematical model had high credibility.

scholarly journals Nonlinear Fluid Models for Biofluid Flow in Constricted Blood Vessels under Body Accelerations: A Comparative Study

2012 ◽  
Vol 2012 ◽  
pp. 1-27
Author(s):  
D. S. Sankar ◽  
Atulya K. Nagar
Keyword(s):  
Flow Rate ◽  
Fluid Model ◽  
Plug Flow ◽  
Casson Fluid ◽  
Fluid Models ◽  
Mean Flow ◽  
Mean Velocity ◽  
Casson Fluid Model ◽  
The Mean ◽  
Nonlinear Fluid

Pulsatile flow of blood in constricted narrow arteries under periodic body acceleration is analyzed, modeling blood as non-Newtonian fluid models with yield stress such as (i) Herschel-Bulkley fluid model and (ii) Casson fluid model. The expressions for various flow quantities obtained by Sankar and Ismail (2010) for Herschel-Bulkley fluid model and Nagarani and Sarojamma (2008), in an improved form, for Casson fluid model are used to compute the data for comparing these fluid models. It is found that the plug core radius and wall shear stress are lower for H-B fluid model than those of the Casson fluid model. It is also noted that the plug flow velocity and flow rate are considerably higher for H-B fluid than those of the Casson fluid model. The estimates of the mean velocity and mean flow rate are considerably higher for H-B fluid model than those of the Casson fluid model.

scholarly journals EFFECTS OF HEAD GAPS AND ROTOR GAP ON FLOW RATE AND HYDRAULIC LEAKAGE OF A NOVEL NON-CONTACT ROTOR BLOWER

2020 ◽  
Vol 57 (6A) ◽  
pp. 125
Author(s):  
Nguyen Hong Thai
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Leakage Flow ◽  
Ideal Case ◽  
Design Error ◽  
Leakage Flow Rate ◽  
Working Performance ◽  
The Impact ◽  
The Ideal

The Roots blower belongs to the non-contact rotor pump family, therefore, there are always certain clearances between rotors and clearances between the rotor and the stator. These clearances have serious effects on the working performance of blower. Therefore, to determine the design error and the method of machining to achieve the lowest price, required machining technology, flow rate and pressure, the determination of leakage flow rate and pressure through the head gap and rotor gap is very necessary. Thus, in this paper, the authors conduct to build a mathematical model in order to determine the flow rate and pressure of blower in the ideal case in which there is no clearance and the case in which there are clearances. On that basis, the authors aim to evaluate the impact of head gaps and rotor gap on flow rate and pressure leakage. In order to improve the working performance of blower and to choose the machining method that is suitable for the applications of this blower.

Effects of Non-Integral Number of PeristalticWaves Transporting Couple Stress Fluids in Finite Length Channels

2011 ◽  
Vol 66 (3-4) ◽  
pp. 172-180 ◽  
Author(s):  
Sanjay Kumar Pandey ◽  
Dharmendra Tripathi
Keyword(s):  
Reynolds Number ◽  
Finite Length ◽  
Flow Rate ◽  
Couple Stress ◽  
Mechanical Efficiency ◽  
Peristaltic Flow ◽  
Long Wavelength ◽  
Integral Number ◽  
Bolus Size ◽  
Couple Stress Fluids

Peristaltic flow of couple stress fluids is studied here in a finite length channel. The analysis is carried out under the assumption of long wavelength and low Reynolds number approximations. When the couple stress parameter increases, it is found that pressure diminishes, maximum averaged flow rate increases, mechanical efficiency decreases, area experiencing reflux reduces, and trapped bolus-size increases. A comparative study of integral and non-integral number of waves propagating along the channel is also done.

Mathematical Model of the Thermal Performance of Double-Pass Solar Collector for Solar Energy Application in Sierra Leone

2021 ◽  
Vol 11 (2) ◽  
pp. 347-355
Author(s):  
Abu Bakarr Momodu Bangura ◽  
Ridho Hantoro ◽  
Ahmad Fudholi ◽  
Pierre Damien Uwitije
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Sierra Leone ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Transfer Coefficients ◽  
Double Pass ◽  
Hourly Temperature ◽  
The Impact

The primary aim of this study was to utilize thermal energy for drying applications on March 21 (day of the year, n = 80) for the climatic weather conditions of Freetown, Sierra Leone. We evaluated the heat absorption of a double-pass solar air collector based on its configuration and exterior input variables before it was designed and mounted at the location of interest. This study considered a steady-state heat transfer using the thermal network procedure for thermodynamic modeling of a double-pass solar collector developed for drying and heating purposes. A mathematical model defining the thermophysical collector properties and many heat transfer coefficients is formed and numerically solved for this purpose. Indeed, this helped us generate the hourly temperature of different heat collector components, which aided in the performance evaluation of the system. The impact of the fluid flowing inside the collector on the temperature of the exit air was analyzed. It was observed that a flow rate of 0.02 kg/s produced an output of 91.72°C. The system's thermal efficiency improves with increased flow rate at various solar radiation intensities. It was observed that the thermal efficiency of the collector increases from 29% to 67% at flow rates of 0.01–0.3 kg/s. Collector lengths of 1.4 and 2.4 m are observed to be economically viable. An increase in the flow rate caused an increase on the efficiency. The hourly outputs for the collector components were represented graphically, and the curve patterns were similar to those of previous studies.

scholarly journals EFFECTS OF HEAD GAPS AND ROTOR GAP ON FLOW RATE AND HYDRAULIC LEAKAGE OF A NOVEL NON-CONTACT ROTOR BLOWER

2020 ◽  
Vol 57 (6A) ◽  
pp. 125
Author(s):  
Nguyen Hong Thai
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Leakage Flow ◽  
Ideal Case ◽  
Design Error ◽  
Leakage Flow Rate ◽  
Working Performance ◽  
The Impact ◽  
The Ideal

The Roots blower belongs to the non-contact rotor pump family, therefore, there are always certain clearances between rotors and clearances between the rotor and the stator. These clearances have serious effects on the working performance of blower. Therefore, to determine the design error and the method of machining to achieve the lowest price, required machining technology, flow rate and pressure, the determination of leakage flow rate and pressure through the head gap and rotor gap is very necessary. Thus, in this paper, the authors conduct to build a mathematical model in order to determine the flow rate and pressure of blower in the ideal case in which there is no clearance and the case in which there are clearances. On that basis, the authors aim to evaluate the impact of head gaps and rotor gap on flow rate and pressure leakage. In order to improve the working performance of blower and to choose the machining method that is suitable for the applications of this blower.

Impact Of Transurethral Resection Of Prostate On International Prostate Symptom Score And Peak Urinary Flow Rate

2020 ◽  
Vol 16 (1) ◽  
pp. 11-15
Author(s):  
Md Waliul Islam ◽  
Md Abul Hossain ◽  
Md Nurul Hooda ◽  
Kazi Rafiqul Abedin ◽  
Husne Ara
Keyword(s):  
Flow Rate ◽  
Transurethral Resection ◽  
Urine Volume ◽  
T Test ◽  
Urinary Symptoms ◽  
Urinary Flow Rate ◽  
Transurethral Resection Of Prostate ◽  
Urinary Flow ◽  
Paired Student ◽  
The Impact

Objectives: To evaluate urinary symptoms and quality of life in patient with BPH before and after TURP. To determine the impact of TURP on the urinary symptoms (IPSS) and peak urinary flow rate. Methods: This study is prospective study carried out between 2010 and 2011 in the department of Urology, National Institute of Kidney Diseases & Urology. Total 102 cases were selected purposively according to selection criteria. Each patient was observed and followed up at 8 weeks (1st visit), 16 weeks (2nd visit) 24 weeks (3rd visit) after transurethral resection of prostate (TURP). IPSS score, QOL score also recorded and uroflowmetry was done to see the peak urinary flow rate (Qmax) of urine and voiding time. USG was done to see post voidal residual urine volume and DRE also done in selected cases. Data was complied and statistical analysis were done using computer based software, Statistical Package for Social Science (SPSS), using paired ‘t’ test. A P value <0.05 was taken as significance. Results: Before TURP, IPSS range 17-25 and mean 21.61+2.43, after TURP, range 0-7 and mean 4.27+1.71). Hence a significant improvement of IPSS was found from 2 months to 6 months follow up after TURP. The change was tested using “paired student ‘t’ test”. Before TURP Qmax range 7-12.2 and mean was 9.96+1.69, which became range 18-25 and mean was 22.61+2.28 after TURP and therefore change of mean Qmax was 12.64+2.69. The change was tested using “paired student ‘t’ test”. The change was found significant (P<0.001). Conclusion: Transurethral resection of prostate resolves obstructive symptoms, rapid improvement of urinary flow rate Bangladesh Journal of Urology, Vol. 16, No. 1, Jan 2013 p.11-15

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

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