Predicting the air flow pattern with proper accuracy and speed inside a building with Natural ventilation is one of the important study topics of building design due to the economic importance of energy consumption. For this purpose, in this study, a chamber with certain dimensions and with Natural connection has been investigated as a study sample to predict the air flow pattern and speed distribution with the help of regional models. Two air inlet and outlet valves were considered for Natural air ventilation. After researching the previous models, the three-dimensional zone model coupled with heat transfer and air flow calculations (ZAER) was chosen as the basis for comparing the modeling results. In the following, after zoning, to improve the flow coefficient factor model, which is assumed to be a constant number, it was assumed to be variable and the results were recorded in different states. The behavior of the model has been checked in the flow coefficients between 0.3 and 1 in order to obtain the most optimal coefficient for the number of suitable cells. Comparing the results of the research with the results of other models and computational fluid dynamics (CFD) showed that the three-dimensional behavior of the flow shows better compatibility with the experimental researches.

The Natural ventilation is an easy way to exchange the indoor polluted warm air with outdoor fresh air. The wind power injects outdoor fresh air into the building. A good indoor air current and subsequently a proper exhaust depend on the openings’ conditions and their situations. A serious architectural question is under what conditions of the openings the wind-cross ventilation can be effective, and the required indoor air current in the enclosure is established. The purpose of this article is analyzing the conditions of indoor Airflow in an analytical architectural model to upgrade the Natural ventilation by focusing on opposite opening’s conditions. This research considers some wind driven ventilation manner with respect to openings circumstances in an assumed cubic model. The research method includes a numerical simulation using a validated computational fluid dynamics (CFD) model. It investigates and compares the performances of different models of Airflow currents in a Natural ventilation process and subsequently the indoor Airflow paths, under the different conditions of the openings in a fixed boundary condition model; the simulations are performed in an assumed model (a 6×6×6m cubic building with just 2 opposite openings in stationary walls as boundaries of the model) by using Gambit and Fluent software. With an analytical method (using Fluent) the gathered data would be analyzed. Finally the results are presented and generalized: the results demonstrate that whatever the wind speed is, the indoor Airflow condition depends on the situations of the openings. It means that the quality of wind-driven cross ventilation and its path is not depended on the wind speed. Besides for establishing proper Natural ventilation, the opposite windows must not be installed in front of each other, or in the same level.

The harvested walnut has a relatively high moisture content of 30% compared with the safe storage moisture content of 8%. One of the common means of reducing the moisture content is by drying. For design of drying and other aeration systems for agricultural products including walnuts, the relationship between the drop in pressure and Airflow velocity must be known. An Airflow resistance apparatus was designed and manufactured to measure the Airflow resistance of walnuts. This apparatus consisted of an air compressor, a rotameter, a cylindrical bin and an inclined U-tube manometer. The pressure, drops at Airflow velocities of 0.085 to 0.55 (m3/s)/m2, were measured at a constant depth of the nuts. Airflow resistance equations were fitted to the measured data. The results showed that, by increasing Airflow rates, an increased drop in pressure was achieved through out walnut column. To study the effect of walnut moisture content on Airflow resistance, the drop in pressure was measured at different moisture contents levels of 8.6%, 15.5%, 21.3% and 27%. Results indicated that the drop in pressure decreased with increasing moisture content, especially for high Airflow rates.

Knowledge of Airflow resistance is an important consideration in designing an appropriate ventilation system and for proper fan selection. An Airflow resistance device was designed and fabricated to measure the Airflow resistance of potatoes. The device the composed of an air compressor, a Rota meter, a cylindrical bin to contain the potatoes and an inclined u-tube manometer, Airflow resistance of potatoes was measured as a relationship between the Airflow rate and pressure drop per unit depth (Pa/m) at 12 Airflow rates of 0.085 to 0.55 m3 s-1 m-2. Two Airflow resistance models, namely, Shedd’s and Hukill and Ives’, were fitted to measured data by using PROC NLIN of SAS. The effect of potato size below 120 g (small), at or above 120g (large) and unsorted (mixed size), and bed depths of 25, 50, 75and 100 cm of potatoes on resistance to Airflow was determined. Results showed that the Airflow resistance of small size potatoes for a 100 cm bed depth was 1.6 times higher than that for large size potatoes, and as the bed depth of potatoes was increased, the Airflow resistance was increased.

The Airflow rate through a two-story building with a courtyard, with and without trees, was estimated and compared with that of a building without a courtyard. The building and the courtyard were of square shapes, each 10 m to the side. The courtyard walls were 3m high and two separate trees of spherical, cylindrical and conical shapes were considered in the yard. The courtyard was directly south of the building and a wind angle of zero degree was considered when the wind was blowing directly from the south. It was found that when the wind angles were between 0 to ± 90 degrees, the Airflow rate through the building was reduced when compared with the building without a courtyard. The presence of trees in the courtyard further reduced the Airflow rate. When the wind angle was 180 degrees, i.e., when the courtyard was in the lee-ward side of the wind, the Airflow rate through the building was increased, and the presence of the trees in the courtyard further increased the flow rate. By considering the wind speeds and directions for the cities of Ahwaz, Kerman, Mashad, Shiraz, Tabriz and Tehran, Iran, the Airflow rates were estimated for the buildings located in these cities. The effect of a courtyard and its trees in reducing the Airflow rates (or increasing it, under special wind directions) were then determined.

Background and Objective: Increasing population and construction of tall buildings have multiplied the presence of environmental pollutants in cities. On the other hand, people use open urban environments more than before to meet their living needs. In this regard, various factors such as the layout of buildings and the presence of continuous wind currents can play a significant role in the distribution of pollutant particles. The present study was conducted to determine the effect of the layout of high-rise residential buildings on the distribution of pollutant particles by recognizing the air flow in Tehran. Method: In this research, using descriptive-analytical and comparative methods, using simulation technique using ENVI-met software, wind behavior around the distribution of pollutants has been investigated and analyzed. The method of data collection has been done through library studies and field survey. Findings: According to the modeling of the two different types of layout of selected urban block (Sobhan residential complex in Gheytariyeh district, Tehran)with similar building form– one as the existing situation and the other as the proposed model with orderly layout, the findings demonstrate that the layout alternation of residential blocks affects the Natural Airflow and wind speed between blocks and an improper and non-methodical locating of high-rise buildings causes a change in Natural wind pattern and consequently, leads to secondary effects resulted from intensification or stagnation of wind and thus, influences the dispersion of pollutant particles. Discussion and Conclusion: In this research, the obtained results from the two models of buildings layout in the software and the output related to the intensity of wind and the retention level of CO show that the existing situation model is more desirable compared to the proposed layout due to more unified and higher wind speed throughout the site and also proper air circulation between blocks which causes the dispersion of pollution and prevents the retention of pollutant particles.

Introduction: Providing clean and fresh air for students in the classroom is of paramount importance, especially in hot seasons. Based on research findings and evidences, mechanical air conditioning systems are not only expensive, but also consume a lot of energy and produce noise. In sultry conditions of Mazandaran province, this issue is more accentuated since the schools are cooled by evaporative air coolers, while it is possible to use the Natural ventilation in a better share of the year, and the schools are closed in warm seasons. Hence, the purpose of this paper is to offer a practical solution that can be architecturally applied to the classrooms to improve the indoor Airflow by inducing outdoor ventilation (Natural ventilation), and provide a desirable and controllable indoor Airflow according to the ASHRAE standard. In most Iranian schools, evaporative air coolers are used in hot seasons to reduce the high costs of air conditioning systems. Observations suggest that evaporative air coolers are also used in hot and humid climate near the Caspian Sea, resulting discomfort, particularly with high levels of humidity. In such cases, the evaporative air coolers are turned off and the windows are opened. Mostly, the induced indoor Airflow is not effective, or a high flow of air enters the classroom in these situations. Problem statement: Achieving comfort at schools in sultry conditions in hot and humid weather of northern Iran is challenging, and thus it is necessary to establish an effective air conditioning system in the classrooms. Moreover, Natural ventilation is the best solution in these conditions according to the climatic and economic reasons. Natural ventilation should consistently induce Airflow in all parts of the classroom at a reasonable velocity. Hence, this research investigates the criteria for designing classrooms in the climate of Amol, considering the position and the general configuration of the openings in the classrooms, and the direction of the prevailing wind to induce a controlled level of Natural ventilation in all parts of the classroom. The main purpose of this article is to address these issues. Research methodology: According to the literature, the present study is interdisciplinary in nature, and uses a combination of methods. The position of the openings and the composition of classrooms were examined as the independent variables, while the status of the indoor Airflow was considered as the dependent variable in this research. The Airflow velocity and direction were measured by precise digital devices during the test periods. The statistical population selected in this study includes all schools of Amol while a random case study was selected for further experimental tests. In the next step, a simulation method was used to analyze the data for evaluating the architectural interventions. Simulations were performed by computational fluid dynamics method: The Gambit pre-processor was used for geometric modeling and grid generation, and Fluent Software was used to analyze the grid. In this study, the k-ε standard model was used to simulate Airflow. Thus, this research uses a combination of methodologies including experimentation, simulations and case study. Results: After examining different tests, an optimal situation was selected according to the following criteria:  Increased velocity of the indoor Airflow in classrooms which (1) is not disturbing and, (2) provides a consistent Airflow for all of the students at all spots of the classroom.  Eliminated vortices in indoor Airflow.  Modified Airflow direction.  Properly directed outdoor Airflow into the indoor space and an induced desirable Airflow. According to the interventions made in this study, it was determined that both windows must act as air inlets to establish effective Airflow in the classroom. The inlet air pressure to both windows must be approximately the same, and the outlet air flow from both windows must be approximately equal as well. This happens when the building facade and the exterior windows have a stepped configuration, and consequently the outdoor Airflow can enter both windows equally. If there is no proper outlet considered for the air entering the classroom, the indoor air flow will be very turbulent. Therefore, devising an appropriate outlet based on the inlet Airflow rate can balance the indoor air flow. According to the simulations, an outlet for the indoor air flow should be made within the wall facing the wind. In other words, if the wind is blowing from the west to the east, the indoor air outlet must be projected on the west wall of the classroom. In this case, the exit door should also be devised in the southwest corner of the classroom. Some air outlets can be created (in the western wall) that act as a fan, a suction pipe, or an air outlet opening in the wall facing the wind, so that the air exits through the pipes in the wall. The suction rate of the western wall can regulate the internal air flow. Moreover, if the wind velocity is too high in the outdoor, the suction devices are turned off or slowed-down, and if the wind velocity is low, the suction devices can discharge more air. In this case, the shape of the indoor air flow is optimized and adjusted.

Knowledge of resistance to Airflow through agricultural products is an important consideration in the design of drying, cooling, or aeration systems and proper fan selection for these systems. Resistance to Airflow of bulk chickpea seeds was studied at moisture contents in the range of 9.21 to 21.36 % (wet basis) for Airflow rate range from 0.02 to 0.50 m3 s-1 m-2, using an experimental test column. The effects of Airflow rate, bed depth (0.25 to 1 m) fill method (loose and dense) and moisture content on Airflow resistance of chickpea samples were investigated. Results indicated that the Airflow resistance of chickpea seeds increased with increase in Airflow rate, bed depth, and decreased moisture content. One percent increase in moisture content decreased the pressure drop about 2.94%. The dense fill method resulted in an increase in resistance to Airflow by about 33.17% more than that of the loose fill. Three models (Shedd’s, Hukill and Ives’s, and Ergun’s models) were fitted to the experimental data at each moisture level and were examined with two parameters. Shedd’s model that gave a higher value for the coefficient of determination and a lower value for the mean relative percentage error of pressure drop predication was found to be the best model to describe Airflow resistance of chickpea seeds.

Nature has aesthetics of its own, what can provoke the human mind into better recognizing the concept of beauty via mental perception. As such, human mind can interact with the nonverbal expressions of nature only to better his/her primitive aesthetic knowledge and reach a more novel recognition of aestheticism via the practice of interpretative deduction. This article has been the result of a series of discussions and dialogues between the authors on the nature of aesthetic geotouring and exploring the Natural phenomena based on the Dialectical Method of Socrates and modelled after the Platonic dialogues. The outcome of this dialectic study brings to light the fact that touring in nature through providing the due opportunity for mental perception of aesthetic phenomena can provide a clearer definition of ‘beauty’ in its rich variety. Aesthetic search as such will culminate in forming a more illuminated mental concept of beauty in mind, what can influence human rationale for aesthetic judgment and enrich even more the texture of human aesthetic creation. Such aesthetico-interpretative endeavor might lead to a higher potential for creating more original works of literature and art and culminate in a better judgment about such aesthetic creations.

Objective and Background: The present study analyzes the urban skyline and Natural ventilation of land parcels in two urban blocks in Velenjak region of Tehran simultaneously. This study tries to assess the efficiency of the urban blocks not only from the visual aspects– what has been considered by most researchers so far-but also from an environmental perspective. For this purpose, a part of the urban texture in Velenjak region of Tehran is modeled in two patterns, and the Airflow with a reference velocity of 4. 5 m/s is applied to the models. The models are prepared in two patterns: 1. The current status; a situation in which vacant lands have been massed according to existing data and ultimately resulted in a heterogeneous skyline; 2. A pattern in which 4 and 5 story buildings are added to the site, resulting in a homogenous skyline. The modeled area comprises 17 urban blocks and has an area of approximately 483, 000 square meters. Wind simulation has been performed by Ansys Fluent Software and k-ε turbulence model, regardless of the atmospheric thermal stratification. Comparing the data obtained from the numerical solutions by Fluent Software to the reference wind tunnel results indicates acceptable accuracy of the selected method. Methods: The information of the nearest meteorological station to Velenjak region is used to assess the data in this area. The data achieved between 2007 and 2016 show that the wind speed is less than 5 meters per second 93% of the time. Therefore, the reference wind speed in this study is considered to be 4. 5 m/s at the height of 10 m. Based on the continuity and the frequency of wind in any direction during the mentioned time, an average for the coefficient of importance is defined for each wind direction (Table 1). In this study, a velocity of 1. 7 m/s at the height of 10 m above the ground is considered the criterion for wind stagnation state. The reference for the assignment of this velocity is Beaufort’ s table. Findings: According to equation 1, a velocity of 1 m/s at 1. 75 m balance is equal to a velocity of 1. 7 m/s at 10 m balance (α = 0. 33). Figures 9 to 12 show the absolute wind speed contours at 10 m balance above the ground on two samples for four wind directions. The areas marked with light blue color are areas of air stagnation. In these areas, the rotational Airflow motion, also known as a vortex or a sequence, can be seen (Figure 7). The magnitude of the sequence area around the buildings is directly related to the building’ s geometry and architecture and the urban fabric formation. Wind speeds in these areas are minimized, and they are prone to the accumulation of pollutants. A point grid with 100×100 points (Figure 8) is considered over the target area at the height of 10 m to compare the sample data and the velocity value at each point. Outdoor points with velocities greater than 1. 7 m/s are separated from points with velocities less than 1. 7 m/s, and their frequency percentages are calculated. Since the importance of wind blow in each direction varies, a coefficient of importance is applied to the frequency percentage of the points, shown in Table 1. Comparing Airflow in two urban patterns with regular and irregular skylines indicates that air stagnation is seen at 29% of time/place in an area with a balanced skyline. However, in the first sample, at about 45% of time/place, the average wind speed at 10 m balance above the ground is recorded as 1. 7 m/s, and thus we experience air stagnation phenomenon. Conclusion: According to the results, considering buildings to cover 60% of the land parcel according to the construction regulations, and given the wind characteristics of the study area and its urban texture pattern, Natural ventilation is provided better in 4 and 5 story buildings with a maximum height of 12 and 15 meters for buildings that cover 60% of the land parcel. This is while 7 story buildings are also allowed to cover 60% of the land parcel due to the relatively highly constructed urban blocks. Based on the results, it can be argued that a balanced skyline is more favorable both aesthetically and environmentally, and that creation of tall buildings in residential areas is only recommended when the building has a symbolic value and plays a special role in the region and affects the skyline.