A new strategy for constructing microgravity culture environment via gas-liquid coupled oscillatory flow field

Sep 30, 2026

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A new microgravity simulation approach is proposed to overcome limits of rotating cell culture systems, which differ from true space microgravity. The method builds a gas-liquid coupled oscillatory system inside a vertical U-tube to create a stable, controllable quasi-free-fall flow-field environment. Physical modeling and CFD-VOF simulations show that during each oscillation period 71% of liquid loses weight in two vertical sections, reaching spatial low microgravity on the order of 10−2g, while pressure and shear-stress dynamics satisfy cell-culture mechanical boundary conditions.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages18

Reading Time45 min

AccessFree to download

Introduction

Motivation and background: microgravity effects on cells

Ground-based microgravity simulation approaches

Rotating Cell Culture System and proposed strategy

Physical principle and design concept

Methods and results

Oscillating flow-field modeling in vertical U-tube

CFD-VOF gas-liquid coupling simulations

Bio-rotary device history

Key milestones in rotator and clinostat development

npj | microgravity Article | Published in cooperation with the Biodesign Institute at Arizona State University, with the support of NASA | | | | --- | --- | --- | | [https://doi.org/10.1038/s41526-025-00546-0](https://doi.org/10.1038/s41526-025-00546-0) | | | | A new strategy for constructing microgravity culture environment via gasliquid coupled oscillatory ﬂow ﬁeld
Check for updates | | | | Chaoyang Wang1, Yan Qiang1,2 & Liejiang Wei1 | | | | The mainstream Rotating Cell Culture System (RCCS) simulates microgravity via three-dimensional dynamic rotation, which differs from true space microgravity in physical mechanisms. In this context, the present investigation innovatively proposes a new microgravity simulation strategy based on Einstein’s equivalence principle—establish a stable and controllable quasi-free-fall ﬂow ﬁeld environment by constructing a gas-liquid coupled oscillatory system inside the U-tube. Based on the analysis of the physical modeling of the oscillating ﬂow ﬁeld in the vertical U-tube and the CFD-VOF gas-liquid coupling simulation experiments with parameters(D = 15 mm, R/D = 1.3)shown that in each oscillation period, 71% of the liquid will lose weight in two vertical sections, and when the liquid at the maximum volume ratio the average weight losspeak value is0.02 g, achieving spatial low microgravity (10−2g), and the dynamic characteristics of the pressure and shear stress of the ﬂow ﬁeld meet the mechanical boundary conditions of cell culture. This approach is expected to establish a new paradigm for ground-based simulation of microgravity effects in space, offering novel technical/ theoretical support. | | | | Microgravity environments (10􀀁2g 􀀁10􀀁6g) have been shown to affect cell morphology and gene expression, and cells are the smallest structural units that makeup living organisms, so exploratory studies ofcells in microgravity environments are very important. While spacecraft such as artiﬁcial satellites, manned spaceships, space shuttles, and space stations are good ways to realize microgravity environments, these kinds of space research experiments require high costs, soto makeup for the lack oflimited opportunities for spaceﬂight, ground-based microgravity simulation technology has emerged. Typically, there are two ways for foundations to achieve microgravity1–3. The ﬁrst method is employs motion techniques to create genuine microgravity. This involves moving objects according to speciﬁc patterns so that nearly all gravitational force is used to counteract inertial or centrifugal forces. In other words, gravity is entirely harnessed to provide the acceleration required for the object’s motion, thereby eliminating gravitational effects and weight perception to achieve microgravity simulation. This falls under the category of environmental simulation. Examples include: drop tower (tube) methods, parabolic ﬂights, balloon descent chambers, and sounding rockets. However, for long-term cell culture studies requiring microgravity biological effects, these methods present signiﬁcant engineering challengesand relatively narrow biological applicability, such asinsufﬁcient duration for extended biological experiments. The other approach employs force balancing to simulate microgravity effects. This | involves applying counterbalancing forces to research subjects within a gravitational ﬁeld, neutralizing gravitational acceleration to achieve microgravity effects or partial effects. This falls under environmental effect simulation. Examples include: water buoyancy technology, air buoyancy technology, wire suspension methods, rotation methods, and other techniques.
Currently, the rotary method is most widely used in the simulation of microgravity biological effects of cells on ground-based experiments3. Many experiments have shown that (some of) the biological effects of microgravity conditions can be qualitatively simulated using a gyratory. The advantages are cost, controlled experiment

FAQs

Why are conventional RCCS methods limited for microgravity biology simulations?

RCCS simulates microgravity via three-dimensional dynamic rotation, but the physical mechanisms differ from true space microgravity, which can limit how faithfully biological conditions are reproduced.

How does the proposed gas-liquid coupled oscillatory U-tube strategy create quasi-free-fall?

It establishes a stable and controllable quasi-free-fall flow-field environment by constructing a gas-liquid coupled oscillatory system inside a U-tube, engineered to reduce effective weight in the oscillating vertical sections.

What simulation results support the feasibility of the strategy?

Modeling and CFD-VOF simulations indicate that within each oscillation period 71% of the liquid loses weight across two vertical sections, producing spatial low microgravity around 10−2g and maintaining pressure/shear-stress boundary conditions compatible with cell culture.

Sep 30, 2026

Upload by Riley