<p>This study delves into a comprehensive examination of the three-dimensional (3<i>D</i>) incompressible magneto-hydrodynamic (<i>MHD</i>) equations in <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(H^{1}(\mathbb {R}^{3})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>H</mi> <mn>1</mn> </msup> <mrow> <mo stretchy="false">(</mo> <msup> <mrow> <mi mathvariant="double-struck">R</mi> </mrow> <mn>3</mn> </msup> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>. The modification involves incorporating a power term in the nonlinear convection component, a particularly relevant adjustment in porous media scenarios, especially when the fluid adheres to the Darcy-Forchheimer law instead of the conventional Darcy law. Our main contributions include establishing global existence over time and demonstrating the uniqueness of solutions. It is important to note that these achievements are obtained with smallness conditions on the initial data, but under the condition that <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\beta &gt;3\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>β</mi> <mo>&gt;</mo> <mn>3</mn> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\alpha &gt;0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>α</mi> <mo>&gt;</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>. However, when <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\beta =3\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>β</mi> <mo>=</mo> <mn>3</mn> </mrow> </math></EquationSource> </InlineEquation>, the problem is limited to the case <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(0&lt;\alpha &lt;\frac{1}{2}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0</mn> <mo>&lt;</mo> <mi>α</mi> <mo>&lt;</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> </math></EquationSource> </InlineEquation> as the above inequality is unsolvable for these values of <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\alpha \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>α</mi> </math></EquationSource> </InlineEquation> using our method. To support our statement, we will add a "slight disturbance" of the function f of the type <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(f(z)=log(e+z^{2})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <mi>l</mi> <mi>o</mi> <mi>g</mi> <mrow> <mo stretchy="false">(</mo> <mi>e</mi> <mo>+</mo> <msup> <mi>z</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> or <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\log (\log (e^{e}+z^{2}))\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>log</mo> <mo stretchy="false">(</mo> <mo>log</mo> <mrow> <mo stretchy="false">(</mo> <msup> <mi>e</mi> <mi>e</mi> </msup> <mo>+</mo> <msup> <mi>z</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> or even <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\log (\log (\log ((e^{e^{e}})+z^{2})))\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>log</mo> <mo stretchy="false">(</mo> <mo>log</mo> <mrow> <mo stretchy="false">(</mo> <mo>log</mo> <mrow> <mo stretchy="false">(</mo> <mrow> <mo stretchy="false">(</mo> <msup> <mi>e</mi> <msup> <mi>e</mi> <mi>e</mi> </msup> </msup> <mo stretchy="false">)</mo> </mrow> <mo>+</mo> <msup> <mi>z</mi> <mn>2</mn> </msup> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>.</p>

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Strong solution of the three-dimensional (3D) incompressible magneto-hydrodynamic (MHD) equations with modified damping

  • Maroua Ltifi

摘要

This study delves into a comprehensive examination of the three-dimensional (3D) incompressible magneto-hydrodynamic (MHD) equations in \(H^{1}(\mathbb {R}^{3})\) H 1 ( R 3 ) . The modification involves incorporating a power term in the nonlinear convection component, a particularly relevant adjustment in porous media scenarios, especially when the fluid adheres to the Darcy-Forchheimer law instead of the conventional Darcy law. Our main contributions include establishing global existence over time and demonstrating the uniqueness of solutions. It is important to note that these achievements are obtained with smallness conditions on the initial data, but under the condition that \(\beta >3\) β > 3 and \(\alpha >0\) α > 0 . However, when \(\beta =3\) β = 3 , the problem is limited to the case \(0<\alpha <\frac{1}{2}\) 0 < α < 1 2 as the above inequality is unsolvable for these values of \(\alpha \) α using our method. To support our statement, we will add a "slight disturbance" of the function f of the type \(f(z)=log(e+z^{2})\) f ( z ) = l o g ( e + z 2 ) or \(\log (\log (e^{e}+z^{2}))\) log ( log ( e e + z 2 ) ) or even \(\log (\log (\log ((e^{e^{e}})+z^{2})))\) log ( log ( log ( ( e e e ) + z 2 ) ) ) .