Journal "Scientific Israel-Technological Advantages" , vol. 16, no.4, 2014

STUDY OF INTERACTION BETWEEN AIR-SUPPORTED SHELLS
AND WIND FLOW

EXPERIMENTAL RESEARCHES

D.Beilin-1, V.Polyakov-2

1- Polymate Ltd.- International Nanotechnology Research Center, Migdal HaEmek, Israel, 2-Moscow, Russian Federation
sitapolymate@gmail.com

CONTENTS

ABSTRACT

INTRODUCTION

1. MODELS

2. FACILITIES AND DEVICES

3. EXPERIMENTAL PROCEDURE

4. PLANNING OF AERODNAMIC EXPERIMENTS

5. DISCUSSION OF THE RESULTS
5.1. Dependence an inner surplus pressure on air flow strength
5.2. Distribution of air flow pressure over surface of the test models
5.2.1. Spherical shells
5.2.2. Cylindrical shell

5.3. Assessment of dissipative processes at action of wind load on pneumatic structures

5.4. Distribution of air flow velocity obtained by visualization method
5.5. Toward approximation of pressure coefficient c(p)
5.6. Wind load on pneumatic structures
5.7. Generalized aerodynamic characteristics and Reynolds criterion
5.8. Study of displacements of air-supported shells under action of internal pressure and air flow
5.8.1. Experiment technique. Stereophotogrammetric method of the displacements measuring
5.8.2. Displacements under the action of internal pressure (example)
5.8.3. Normal relative displacements (w/R) of the shells with spherical and cylindrical shapes under air flow action
• Model of trunked spherical shell (H/D) = 0.85
• Model of trunked spherical shell (H/D) = 0.7
• Model of trunked spherical shell (H/D) = 0.3
• Model of cylindrical shell with spherical ends

5.9. Special issues of real behavior of pneumatic shells in the air flow
5.9.1. Formation of folded zone in a spherical shell is a result of the wave processes by reaction with the air flow
5.9.2. Parameters of the zone of flow deceleration
5.9.3. Strains of material of the model

ABSTRACT

Analysis of the stress-strain state of pneumatic membrane structures under wind loads is the most important problem during in the design process. Studying of the wind pressure distribution through of the air-supported shells surface and changes of their shapes in an undisturbed air flow was performed during the wind tunnel tests .The large-scale air supported shell models with truncated spherical and semi-cylindrical forms were tested. The tests were carried out in the super critical streamline area (Re =106 ÷ 107) corresponding to the auto model process of flow. In the course of the experiment the distribution of through shell surface, aerodynamic performances and changes of inside surplus pressure and displacements of the shell surface's points were studied. Paths and magnitudes of the principal tension stresses, "critical" inner pressure giving rise to unidirectional areas of stress state and the boundaries of these areas were established.